Would an FPGA not be able to handle multiple jobs, if big enough?
Yes, doing lots of different things at once is exactly what an FPGA excels at.
There's already a PCE FPGA core that runs on the MiST and Altera boards, but it's not fully "accurate", and AFAIK, doesn't play every HuCard properly.
There's no PCE CD support that I know of, but I might have missed some continued development.