I guess I can answer my own question. Correct me if I'm wrong but it appears that basically there are 2 supported WIFI PC Cards. They are the IBM High Rate and the ARtem Onair Comcard. Both these cards are pretty rare. I found the High Rate in a few places, but at $79.00 and up, well, that's a little steep for an 802.11b today. I couldn't find the ARtem card anywhere.
www.os2warp.be doesn't seem to allow downloads to the few additional drivers available. This website
http://en.ecomstation.ru/hardware.php is a good one. I was able to find that the D-Link MA401 is ECS compatible using the IBM High Rate Driver. So, I bought one and sure enough I'm writing this message on my 600E running eCS 1.2 and a D-Link MA401 WIFI card.
I still can't get eCS to recognize anything plugged into the USB port. I've tried a Microsoft wireless mouse, Memorex 4gb flash drive and a generic 512mb flash drive.