V-brake / cantilever pad alternatives for carbon rims?
It turns out the best way to go about this is to buy threaded cyclocross brake shoes that take regular road pads. A few:


Avid Shorty 6 TRP 
TRP Inplace Adjust M
Jagwire Cross Pro 
Kool Stop Cross Threaded 
Clark's CP453CV
Tektro 720.12