OK, I don't own a 570, but I think this is how it works:
First, the 570 actually uses the same drives as the 600 except that you have to remove a thin plate off of the bottom-front of a 600 drive in order for it to fit into a 570. There are some 600 drives that you cannot remove that plate from.
Second, I think the 570 uses a standard 12mm CD/DVD drive. The raw drive is held inside a black plastic frame or tray with a bit of metal and a tiny bit of electronics. You can replace the raw drive inside such a frame by unscrewing 4 or 5 screws, separating the internal plug and pulling it out. Then, theoretically, you should be able to put in almost any 12mm drive. That includes CD-RW/DVD or DVD-R/RW drives.
So, on eBay, you can find drives like these:
IBM Thinkpad 8X DVD±RW Burner 570 600 600E 600X (New)
or
DVD±RW/CDRW Drive for IBM Thinkpad 570/600/600E/600X
No endorsement of these auctions is implied here. I just picked them because they were the first to show up in my searches. I have no experience or knowledge of these eBay sellers.
These auctions are not for original IBM drives, but rather new drives that have been retrofitted into the UltraSlim Bay drive trays.
Phil.