The Art of Richard Thompson is available in French
As of last fall, The Art of Richard Thompson is available in French (in Europe at least) from Urban Comics of Paris. They have done an excellent job on the book production. Cul de Sac is also reprinted by them in three volumes. The American version is sold out from Andrews McMeel. The Incomplete Art of Why Things Are (The Richard Thompson Library Volume 1) is still currently available.
The note says that translated versions of the comics have been added at the back of this edition.