FPGA Replay Arcade Ideas for other Daughterboards

[freqmax]

You'd probably need drivers for them.  Who would write those?  Are you planning to run AROS or OS 3.9 on them?

Dude.. FPGA Replay is a re-implementation so any drivers are already written..

As for extensions, another FPGA would enable even more cool stuff

[freqmax]

The only limitation is our own imagination. And resources to design and order PCBs. The hard parts on the FPGA Replay is the DDR interface and the BGA soldering.