Jay Smith sometimes has some but only the Slania engraved ones -
http://www.jaysmith.com/Topics/Slan...-Stamps.html They are usually quite rare and collectable = expensive.
There is a nice site though for these items -
http://www.dieproofs.it/As you can see there are various types of French proofs the main ones listed in Maurey are:-
Epreuves D'Artise - Artist/engraver proofs
Epreuves De Luxe - Proof mini sheet
I have also seen some here -
http://www.postlynx.com/index.php?m...Path=104_284