My various 650B conversions are likely scattered through this thread, but here they are in one post:
Currently in the fleet:
Lemond Buenos Aires with 38mm tires:
St. Etienne porteur (originally made for 27" wheels) with 32mm tires:
No longer in the fleet:
'94 Trek 2120 with 32mm tires:
Trek 330 Elance with 38mm tires:
'72 Peugeot PX-10 with 42mm tires:
J.P. Weigle with 32mm tires
'78 Raleigh Competition G.S. with 38mm tires
Centurion Semi-Pro with 38mm tires