Behold, Gilles Berthoud stainless-steel mudguards, 50mm wide and perfectly formed to sit over the 42mm Grand Bois Hetres! After considering the Velo Orange Zeppelins, and measuring frame clearance front and rear, I realized that anything over 50mm was going to really challenge my metal-forming skills. As they are, the GB fenders will require a small tapering to get inside the front forklegs, but the rear looks like it was made for the frame.
Anybody worrying about the weight of stainless steel in this application should take a pill; I have plastic mudguards sitting around that weigh more than these. The lovely polished finish and little roll on the front and rear lips of the guards are really great. To integrate them with the bike overall I'm going to lay some pinstripes on them to match the copper and dark green trim on the seat tube.