non-rechargable battery powered music systems for iPod

Hello everyone, I was hoping to get some input from some fellow iPod users with regards to playing my and a buddys ipod through a battery powered music system. The problem seems to be that we do a few canoe and fly-in fishing trips and will not have any way to recharge our iPods. In the past we have always taken portable battery powered computer speakers, portable cassette walkman and tapes, portable cd player and some cd's. After taking into consideration all the weight of these items plus the needed batteries, it seems a shame not to take a stand alone player that will take batteries that could play as well as charge our iPods that contain thousands of songs.
So I guess I'm looking for some guidance in trying to make a purchace. Any input would be greatly appreciated.
Thankyou for taking the time to read this lengthy post!