@doctorq
Nice idea, but they don't autoboot. Still he could have a boot floppy in df0: with the drivers and startup-sequence to run a harddrive off the XSurf...kind of like an old A1000.
If polled I/O transfers to harddisk and autoboot is all you want, just make a homemade ISA-Zorro hack a la the Slingshot and slap an old DataFlyer SCSI, IVS, ICD, Supra or other SCSI 1 controller off the 86-pin expansion port. This works and would give you an autoboot harddrisk and scsi cdrom access. Later an accelerator, clockport adapter or other could be added internally to the 68000 socket. Or if you could find one, an ICD AdRAM 540 or Expansion Systems Baseboard would give you 4MB fast ram in the A500 belly slot.
Jens (Individual Computers) btw is supposedly making an A500 version of the Buddha controller, but it's not available yet, afaik.