If a stereo monitor on the stage is important to you and you don't want to carry 2 powered cabinets then check out the Motion Sound amps at http://www.motion-sound.com/ There has been quite a bit of discussion about them on the General Arranger Forum on this BBS.

If you are up to carrying 2 compact powered boxes then the biamped Behringer B300 is hard to beat for $350 per box with 300 Watts, horn and 15 inch speaker. It is also a very convenient size for carrying in a car.