On 9/5/07, Chris M <chrism3667 at yahoo.com> wrote:
  I had been wondering if there were
 boards for a pc that supplemented the operation of the
 onboard mpu by providing another processor
 altoghether, and in no way replacing the old 8088,
 thereby in effect giving you 2 pc's in one. Of course
 there were z80 boards, 68k? boards that accomplished
 this. 
There were the HP Viper 82300 and Hyper-Viper 82324 68K based boards
for running Rocky Mountain BASIC on a PC.
ftp://ftp.agilent.com/pub/mpusup/pc/old/vp_over.html
(I hope people have archived the above directory for the day when that
info disappears...)