I cant see any real problems with WiFi to be honest, other than I seem to remember Mentorn not being too happy about data being transmitted back from the data (although this was intended for telemetry AFAIK). It wouldnt be easy, but itd be an interesting project.

I looked into the ISAAC systems some time ago and couldnt see it being an easy task to make it operate on UK frequencies, I think they are intended for 75MHz.