I'm not familiar with their current lineup, but the VX-5 had a disposable battery option that was 2xAA. The gotcha is that it doesn't provide enough power for full xmit power (I think only .5W).

Note, it does have an external power input, so you could build your own battery pack. I have a thread over on CPF on that topic I could dig up if poked with a stick.

-john