well, since my whole family is into amateur radio, i decided to mount a very small, dual-band (VHF/UHF) transceiver to my bike. i found an old plastic mount in my junk drawer (dont even remember what its for), and attached the radio to it. a few wraps of tape around the bar tightened up the mount perfectly, and the speaker mic is very handy to grab while on the road. or better yet, off to the side if i need a pick up. this particular radio can also get AM/FM, so lo-fi tunes are possible. nice on a long ride on back roads.
anyway, just thought i'd share the idea. i'm sure one of those FRS rigs would work too, assuming a drilled and tapped hole on the back, but i dont know if you can get a speaker mic for those.