Mine is the 4 chip version, as in your pic. I guess the only thing you'd need to do at that point is put the ROM's on a card with the pin-out that matches the weird interface it has. It should also be possible to combo an FPU on the card as well, if I remember correctly, then you'd really have a sweet product on your hands. FPU + ROM expansion.

One would probably want to re-write the ROMs on the logic board as well to reclaim the 1/2 megabyte that is just sitting there blank, that would give one 3 1/2 megabytes of contiguous ROM to play with, since all 4 megs gets put into a contiguous memory space despite being split between the motherboard and the card. That's quite a hunk of space. I have no doubt I could get System 7.1.2 down to 3 1/2 megs easily.