AFAIK CompactFlash cards "speak" ATA/IDE and all you need is a simple
adapter to make them into a "disk" (bootable too). newegg has a couple
adapters for $10 and 8GB CF cards can be had for as little as $125...
Might be a little more effort but it's a lot cheaper, plus you could
conceivably swap flash cards (or carry a backup) if you need to.