There is a book called Standardformulierungen für deutsche Vertragstexte mit Übersetzungen in englischer, französischer und spanischer Sprache, in the terminological series issued by the German Foreign Office. Apparently it’s out of print – my third edition is dated 1992 – but there will be a new edition, probably in spring 2005.
Although the emphasis of the book is on international treaties, it is extremely informative for other types of contract translation too. It has a large number of clauses in four languages, and above all it explains how to proceed when translating and why.
The Foreign Office has a list of the publications in this series online.