Has anyone built ISA bus cards for non-intel/zilog CPU's?

As a side effect of my work, I have a rackmount system with just a passive
ISA bus instead of a motherboard as a "PC".  Since the CPU's we use --
originally '386 and now Pentiums up to 4 -- are all just another ISA bus
card, I was wondering if there's any written record of anyone doing a CPU
card for, say, a Motorola 68K or something like that.

    TIA
        Norm