Yep, there's a few canti options (I'm using tektro cr720s) or you can splurge for Paul motolites which will apparently let you fit all the way up to a 700c in a 26 frame. But since I got this frame for $20, I didn't really want to spend 10x as much on the brakes alone.
Nice man. How did the 26" to 650b conversion work? Just a case of buying the right cantis?