You should try the "Big external enclosures" thread in the optical drives forum. http://club.cdfreaks.com/showthread.php?t=119149
How well these enclosures work may depend on what chipset they use.
I have one of these: http://www.dealsonic.com/usb20enfor52.html This one uses the Cypress AT2+ chipset and it works perfectly for me. I use Liteon drives which may be less picky than other drives.
Mine will allow me to format DVD+RW discs. Many controllers don't handle this format command. I can boot my computer from it and even install XP without using floppies.
It's also excellent for hard drives and allows access to the drive's S.M.A.R.T. status and drive self test.
If you do get one of enclosures you mentioned in your posts, you might want to let us know how they work by posting in the big external enclosures thread.