Dear Spork!
Unfortunately, there is no such thing as a "German Douay Rheims" Bible, as there is a multitude of different translations around. The latest translations are, of course, extremely modernist. The Novus Ordo uses a translation meant to "unify" Protestants and Catholics and to be used by both - but the Protestants rejected it, as it is just too crazy.
Also, Germans are not as fond of the usage of antiquated language in liturgy or scripture as the English are.
In any case: Try to find the translation of Joseph Franz von Allioli ( †1873), ("Allioli-Bibel"), much used in the latter part of the 19th and beginning of the 20th century.
The language is of course somewhat antiquated, and older versions might be written in Gothic ("Fraktur") font.
I don´t even have the Allioli-Bibel myself, I am using the "Hamp-Stenzel-Kürzinger" edition of the early 60´s, not exactly the ideal and based on the Hebrew, not the Vulgate.
You are looking for a German Missal? Look for "Schott Messbuch", they reprinted the 1962, but older versions are largely available.