i have a 1997 buel cyclone that i want to take the engine out of and put into a "chopper frame( rigid or softail). i love the power and torque of the engine, but the cafe style bike crushes my junk. can i swap out 1200 sportster lower cases with the ones on the buell motor so that i can bolt it (buell motor) to a different frame? if not, will the buell lower fit into any other style of lower that is compatible with a regular frame?

Your Buell engine cases are in fact the same as Sportster cases. Just pull the engine and re-install it in the new frame. I just replaced a 883 Sportster engine with an engine from my 1999 X1 and it was a bolt in swap.