I had a bunch of "PCMCIA to CompactFlash" adapters; which would've been perfect for this. They're a passive thing, CF cards go right on the bus and poof its an

I had a bunch of "PCMCIA to CompactFlash" adapters; which would've been perfect for this. They're a passive thing, CF cards go right on the bus and poof its an IDE device you can boot from. And you can still write CF from anything. I suspect they're still commercially available.