Electro Voice Everse 8 and Everse 12 are highly regarded, but total overkill for campfire duty IMHO.I used a battery-powered PA speaker one time to play for an outdoor wedding ceremony where no power was available and a generator would have been a noisy nuisance. I can't for the life of me remember what the brand or particulars were, but I remember that it worked extremely well, and that I remember thinking; I should really have one of these!
Then again the Cube Street EX is about the same price as the Everse 8, and I am pretty sure the Everse will play way louder.