I have a tubing bender from these guys
Pipe Bending Machine (not this model bender, mine won't do 180º bends, but this one will) they sell dies sized for tubing (based on actual O.D. & wall thickness) or sized for pipe.
PROTOOLS 1/2" pipe has the same O.D. (.840") as thick wall conduit, the thin wall conduit is .820", I'm not sure how the bend quality will compare with the mismatch in diameter, but I doubt it will be a huge difference. they do sell the die's in the 4.5" radius and are available in 240º bends (to complete a 180º bend)
PROTOOLS this is the model I have and have been happy with it. (hasn't gotten much use lately though)