I know of a few people that have bent a few to fit from other applications, but nothing that i am aware of is a direct fit without it being made directly for a Cannondale / ATK.
I know the Robbins bros when they raced C'Dales used YFZ bumpers on theirs. Both had stadium ones that they tok off YFZ's and bent. Said it was real easy to do as they were pretty close. Never done it or looked at them too closely myself though. Thought it was funny though b/c when they switched from C'Dale to YFZ's they just switched the bumpers back.