I have been researching this for weeks now. and I have one on it's way to me...
the Yaesu FTM-10R dual band water and dust proof motorcycle radio.
It does 2 meter, 440, has a FM/AM receiver, allows ipod input and can wire up to two headsets and has intercom between them as well as audio sharing. It also has a stereo audio amp to drive my speakers in the faring. On second gens it looks like it would fit in the cassette location. on first gens it can pretty much mount anywhere. This will allow me to stay single antenna and still feed my ham radio hobby.
and if I want to be "naughty" I can mod the radio for Marrs and CAP operation and transmit/recieve on the FRS frequencies to talk to the other guys in the riding group. 440mhz on low power is 3 watts, so if you stick to the high channel numbers and get a GMRS license you will be "technically" legal. just transmitting on a radio without the correct FCC type certification.