The list of chipsets is on the Posseidon USB stack website.
http://www.platon42.de/index2.htmlPegasus, Pegasus II, ASIX, Davicom, MosChip and RealTek Chipsets.
I use one intended for the Nintendo Wii (it's an ASIX), works great. I assume there aren't many drivers in the Wii firmware, so it's probably a safe bet, is available everywhere and doesn't cost much at all.