HondaGal and I use the Autocom units and the Autocom VOX headsets. They work great! We've chatted at speeds up to 70 mph. They would work better if I move my mic a bit, sometimes wind gets up under my helmet and kicks the mic on. We use the Kenwood Family Radios, as they got the best ratings. Also plugged into the Autocom is my XM radio. You could plug in a tape, disc, mp3, etc. as well. We found some demo, slightly used Autocom units for a good price, from Autocom. I've been very pleased with them.
Edit: The US distributor for Autocom is Top Gear Accessories:
Top Gear Accessories
P.O. Box 1477
Slingerlands
N.Y. 12159
U.S.A. Phone: +1 888 851 GEAR
Fax: +1 518 449 8876
They don't have a website. They are very helpful over the phone.
I think there is a uk website that may have product listings.