in regards to building an x86 Amiga accelerator...
You could also have all the fastmem you want on the accelerator board, as there are no 24-bit address limitations in that jungle. The RAM speed could also exceed the traditional by far.
Very true.... Of course, you'd exceed the speed of the whole old Amiga by far. At that point, why not virtualize (a skeleton) of it. Then you've ended up back at Amithlon. Take away the copyright problems from that, and you're at AROS.
I just don't see the classic hardware having a future beyond that of retro/collectible.