this is an interesting thread. I started a thread in my local section about some that im making using C6 projectors in a stock headlight. some of my info might be helpful.
Dave is at it again
for the headlamp part i cut out the mount from the C6 and grafted it into the Camaro headlight. the high beams projector i was able to screw straight into the Camaro headlight, then seal it in. it all fits behind the lens no problem.
EDIT: I do agree that you cant just swap around parts. the main reason why you need to use the entire assembly is that the distance between the light source and the lens is crucial to getting the right cutoff and effect. the arc of the lens is designed with that distance in mind, and of course, the "bowl" is also angled with the distance in mind.
EDIT II: Ill also add that the C6 projector is the shallowest ive seen. it fits really well into the camaro housing. you might want to try and get a set to fool around with.