I would use the search function but I have no idea what this kind of pedal is called. I've seen them on a select few bikes in various bike galleries, the ones that are clipless on one side and either clipped or flat on the other.
1. Do they have a specific name?
2. What's a good brand to look for? I've heard good things about Crank Bros, but unfortunately it appears they don't manufacture this kind of pedal. Either that or what's required is a modification of the pedals I have.
3. Where to buy? I've used eBay, Amazon, Ben's Cycles, and Tree Fort Bikes as online resources when I'm not at Citibikes.