I think people suggested that the Zydas usb one should work, if the driver could be fixed up. There was another make too which I think someone was working on, but I forget, it'll come back to me what it was.
Ah yes, the ralink adapter - the guy who was looking at it liked it because it also did WPA by itself rather than needing wpa supplicant etc.
Sorry, that's as much as I can help you with, but I'd love it for you to succeed! Next time I can borrow a cheap wifi dongle I'll see what the Z makes of it.