There is a driver for some USB Ethernet cards with the Thylacine USB card but as that is Zorro only it probably doesn't help the original poster much.
There are now software patches on Aminet which negate the need for a hardware CC_Reset fix if you use a PCMCIA card. IIRC you need CardReset.lha and CardPatch.lha, both in util/boot on Aminet. Further details are in the lates cnet.device docs. One of my friends has an A1200 with a PCMCIA Ethernet cards and went from a hardware CC_Reset fix to using these software patches and they seem to work well.
If you can find a compatible PCMCIA card it is probably the cheapest way to go.
