The JM20330 based adapter Mark showed above worked for him, which gave me some hope that the QNINE one I bought off Amazon (which also has a JM20330 on it) would work. The JM20330s have built-in firmware/microcode/whatever, there's no external chip holding firmware that the vendor making the PATA/SATA adapter can fuck up. Snoopstah's success post gives me more hope

I've got one of these old things: http://www.vantecusa.com/products_detail.php?p_id=52

Plugging one of the old Empeg drives into it, my desktop sees the drive OK, so PATA side of the adapter is fine. Two SATA drives I have (256gb SSD, 500mb HDD) work with the SATA side of the adapter. But neither of those drives, through the QNINE adapter and plugged into the PATA side of the adapter, work.

I stole a 40<->44 pin PATA adapter from the junk bin at work, I'll try it tonight in my desktop to see if the QNINE springs to life, but I'm pessimistic.