Putting a fast accelerator in an old Amiga might be more comparable to putting a BMW M3 engine in an old Volkswagen beetle (ready for the autobahn?).
It certainly makes more sense to put it in an A1200 or A4000 than it does in an A1000/A500/A600/CDTV.
I'd like to see how a hardware framebuffer c2p/15bit->ham8 conversion would pan out (equivalent of
http://aminet.net/package/misc/emu/AmigaAGA-EVD12). Also texture mapping in hardware might be interesting, OpenGL rendering to AGA FTW.
But just a 500mhz 030 equivalent would sell a lot if it could be made cheap enough.