I know some of you run or attend a slam that has no amplification. This is a pretty good and reasonably low cost option to solve that problem. Please check out the Ion Audio Block Rocker here http://ion-audio.com/blockrocker
Now, I want you to know this is not spam and not an advertisement. I also have never seen nor heard this system, but I just read a 5 star review in Mac|Life. Their short review: Lots of input options. Easy connectivity to external amp or pre-amp. Full rich sound. Very portable. And the Cons: Could use built in EQ.
And the best part is it has a 12 hour battery! Use it on the street corner if you want. Just plug in the mic and go.
Two other cool ideas: 1) It has wheels and a handle like a roller suitcase! Great since the whole thing only weighs 35 pounds. 2) You can just drop your iPod into the built in dock for the intermission or to back yourself up with that jazz band! I think this solves almost all of my complaints about hauling speakers, boards, wires, and every other damn thing for about 15 years. You young folks have it soooooo easy. I remember the olden days when we had to carry speakers carved out of rocks, uphill both ways, and still try to avoid the big meat-eating lizards in the primordial swamp and the primeval forest.