Biggest problem I can see is relocating the latch.
The seat itself is pretty straight forward. Its a plastic pan, foam padding, and a vinyl cover.
Celli mentioned that he
put in some extra padding when he did his. I'd shoot him a PM about the pillion-ectomy.
As for the seat cowl, I think it might wobble around a little bit without the support, but not much. If it does, it wouldn't be really hard to reinforce it. Without the seat there, you have all sorts of options.