It does sound like you are building a new computer here. Why not
just do a PCI card that could work in a PC or Mac. Perhaps work in
both. Like the //e card for the mac. Now I know the ROMS might be
problam, but most people that would be interested in buying such a card
would actually have a couple of //gs's around. So just pull the ROMs
off them. Although I do see the problem of would the card use ROM 01
or ROM 03 or both.
Now, I konw this stuff is way over my head, but that's what I am
thinking after I read all these messages about a card for the Apple II.