Hi,
I think they do.
The only really nice approach to a wireless cam is this:
YouTube LinkFrom what a quick glance has told me, apart from 10m range Bluetooth webcams, the rest is simply CCTVs with WiFi interface (which would be quite useable to the OP), or a digitizer is needed at the receiver end and with a few IP-cams sprinkled in here and there, so not what I would referr to as a webcam. I don't see any use for a long range webcam either, as they're mostly used for video chats and such. Seems like the word webcam is stretched a bit those days. I don't call my CCTVs for webcam, not even the IP-cams, as they're for something entirely different.
An IP-cam would be another solution, but they're not exactly cheap, even though prices has gone down.