I think I'll do what you guys suggested.. just stick a couple of speakers together with a lepai and call it a day.
I do have these old Cambridge soundworks cubes that were part of a really good 2.1 setup. The cubes work but the amp+sub is long gone. Maybe I'll just build a little sub and add the cubes into the box.
If you don't want to use really heavy deep cycle lead acid batteries, (lithium-ion and lithium-polymer) batteries are expensive and also DANGEROUS unless they have the correct charger and you know what your doing.
It's the Dayton Audio DTA-1 Class T Digital AC/DC Mini Amplifier 15 WPC
And runs on 8x AA batteries or can be AC powered as well. I would use 8x nimh rechargable batteries in there.
I like the Sanyo Enloop ones the most for high drain applications.
If you want extra sparkle a pair of piezo tweeters with a 3 watt(or higher) 10 ohm resistor on the positive terminal side of the tweeter which tones down some of the harshness and stops the amp from osscilating. Also as the frequency rises, the impedance continues to drop on a piezo so can damage the amp if it drops too low.