Spock,
Can you find out what chip is on the card (ie. RealTek). If you find that out, you can find another card that uses the same chip and use their drivers. It may work, just as well as it may not.
I had an extra Hawking SOHO series 10/100 card lying around the office when the ethernet port in my Beige G3-333 blew. I went on their website and they had no mac drivers for the card. Being the resourceful person I am, I found what chip it was using (Realtek RTL 8139) and searched the internet for mac drivers for the same chip and came up with one that worked.
The best part is, the card was only $19.95.
Good hunting.
in8