Not only don't I know too many 22 year olds who are capable of translating Rashi, but this volume featured his learned footnotes and 33-pages of introductory essays, signed 3 Elul 5592.
The essays gave a synopsis of parshanut, a small biography of Rashi, a section on Tradition (=Oral Law in the Torah), another on Symbolism and Allegory, Middah Ke-negged Middah, Personification, Smichus ha-Parshios, Hebrew linguistic puns, and Gematrios. At the beginning of the volume were haskamos, or congratulatory letters, from the Chief Rabbi of Prague, RabbiShmuel Landau (son of Noda Beyehuda) and R. Shmuel Freund, who was on his Beis Din. In addition, there is a letter to Dukes' father from Moshe Landau, who was R. Shmuel's nephew, the printer of this work, a community leader of Prague, and a famous scholar in his own right. Toward the end there is a 12 page letter, including an epic poem, by Dukes' very good friend and Pressburg native, Mendel Stern.
But without a doubt the coup de grâce is the effusive haskamah from none other than Rabbi Moshe Sofer, the Chasam Sofer, demurely placed after the work proper (after the Rashi translation is about 30 pages of haftaros, and then the haskamah). This haskamah was singled out by both R. Landau and R. Freund in their own approbations. Here it is:
Essentially, the Chasam Sofer writes that Dukes learned in his Beis Midrash from his youth, and grew in studying Gemara, Rashi and Tosafos, and afterward entered "other vineyards," and grew wise in secular studies and languages, and he did well. Upon seeing him back home in Pressburg, he was impressed with his continuing piety and fear of Heaven. He presented his rebbe with his translation of Rashi, from Hebrew to German, and "I saw a great purpose for it," because many Jews in these days speak a foreign tongue (=German) and only read books printed in foreign languages. Furthermore, most translations of the Torah only adhere to the peshat (plain, literal sense) without giving attention to the interpretations of Chazal. But Rashi, the foremost commentator, who followed closely in the footsteps of Chazal, brings the Sages' interpretations that are closest to the plain sense. But since his commentary is in Hebrew, only a few in this generation learn it - it is almost being forgotten!
However, a very mighty young man, a scholar and expert in [these] two languages, who understands Rashi and knows where to find his sources in the writings of Chazal, has translated Rashi into German - this is a great thing for the Jews. He presented to me his translation of all of Genesis with its wonderful introduction (emph. mine), and I looked at much of it, and found it to be correct, and his words beautifully illumine the subject. Therefore I "place my hands upon it," and once it is printed I will purchase one copy at whatever the asking price is, and others should do the same as me, and help support the work of [Dukes].
Not bad, huh?
Interestingly, there is a behind-the-scenes look at the matter of obtaining the haskamah. Although it seems clear that Dukes personally met with the Chasam Sofer, and presented him with a copy of his work, evidently he did not receive a haskamah straight away (which makes sense, since naturally it would take some time to look over the work - the approbation happens to be dated 2 months after the introduction, which must have been written after the translation was completed). It seems that Dukes' friend Mendel Stern actually picked up the haskamah from the Chasam Sofer, and sent it to Dukes. Mendel Stern, by the way, would go on to publish the influential journal Kokheve Yizhak. At the time he was employed by the Chasam Sofer to teach his children Hebrew language and dikduk.
In any case, Ignaz Reich's Beth-el: Ehrentempel verdienter ungarischer Israeliten included a biographical sketch of Leopold Dukes in its first volume (1867). Aside for the interesting fact that Dukes was so pious (per the essay) that he wore Rabbenu Tam tefillin after his Bar Mitzvah, it includes a fascinating letter, dated München 4 November 1832, from Dukes to Mendel Stern. If all that I have written about the haskama thus far doesn't impress you, dear reader, in the article itself it says that Stern obtained it from "dem als hyper-orthodox verschrienen Sophar!" - "the one who is decried as Hyper-Orthodox, Sophar!"
Dukes had just received the haskamah in the mail, and the letter is his acknowledgement of its receipt. Dukes thanks Stern, and then referring to "Die Haskomoh von meinem Lehrer — (den Gott lange erhalten möge!)" says, rhetorically, that one knows the drill about all haskamos (=they exaggerate about the greatness of the author). He will need to work hard to make everything written in the haskamah true about himself! He then says that the haskamah makes him respect the Chasam Sofer, whom he has long respected a great deal, even more. He didn't really expect to receive a haskamah, and if he did receive one, he thought it would be only a few lines so that a former student would not go empty-handed. But now that he sees it, it's a different matter - the Chasam Sofer is perfectly happy with his work! Both Dukes and the pious buying public ("dem frommen kaufenden Publikum") can't be happier with such words as those written by the Chasam Sofer.
He then asks a very good question: Who knows if anyone had done this 20 years earlier, if the Chasam Sofer would have said the same things! This Godol ("der große Mann") is attuned to the "Zeitgeiste" (the spirit of the time). Evidently he ignores the shrill, ignorant "Frömmler" (bigots) in their dear hometown (=Pressburg). And what a bad light this haskamah puts these Pharisees (!) ("jene Pharisäer") in, those who combine ignorance and conceit! Many things would not have happened if two decades earlier the luminaries, the rabbis ("die Koryphäen unserer Rabbinen") had given a little attention to the spirit of the age. They could have saved themselves and their orthodox brethren some annoyances. What they did not then do willingly, they will be forced to do by the times.
On the one hand one wonders if the Chasam Sofer would have been so keen if he had known what Leib Dukes' private thoughts were. On the other hand why should anyone think that the problem of today's generation didn't exist then? Furthermore, according to some, private thoughts don't count. Of course either way the facts laid out by the Chasam Sofer do not change: in his opinion it was a very good work, and very badly needed.
Dukes would go on to complete the work in four more volumes, printed in 1838. He also spent many years in the greatest Judaica libraries in Europe, including a 20-year stint in England where he worked at Oxford's great collection in the Bodleian Library, publishing and revealing much of our great works of the past. He died in 1891.
 I mentioned that I am impressed at the ability of this 22 year old, but in fairness it should be pointed out that a translation of Rashi into a European language already existed. In 1710 Johann Friedrich Breithaupt published his Latin translation of Rashi, R. Salomonis Jarchi, Commentarius Hebraicus, etc.. Dukes refers to it in his own introduction.
Interestingly, in the same year (1833) one L. Haymann printed Rabbi Salomo Jarchi's ausführlicher Commentar über den Pentateuch in Bonn. This translation of the Genesis commentary was entirely in German letters and although I cannot say if there was anything in it content-wise of which the Chasam Sofer would not have approved, the format indicates that it was from and for a different world (it didn't even include the Hebrew text of Rashi, as Dukes did). Considering CS's gloomy prognostication about Rashi in his time - see later in the post from above (if you actually came to this footnote in its proper place in the post) - it seems that the immanent existence of Haymann's volume should cast at least a little doubt on that same gloomy outlook. Clearly there was a perceived audience for Rashi in German, even if Haymann's was apparently more connected with European Bible scholarship than the edification of a lay Jewish public. There can be little doubt that Dukes and Haymann worked entirely independently and neither's edition has anything to do with the other.
If anyone is interested, here is the book's front matter, which included our friend Karl Fischer, the censor of Prague's, note. He too references the Breithaupt translation: