The cards I'm using on my PC are RTL 8180 based, I have no idea how different these are from the Realtek 8139 cards 100mb cards supported.
I emailed Elbox about it and they referred me the network card page. Sometimes its a bit tricky to find out what chipset is used in a card.
Having said that I think that the easiest option in the Wireless Bridge, thanks for the link Jason.