You might want to check these out.
http://www.alesis.com/products/sumo/index.html


Ive played them at guitar center...kinda a funny story. Was playing on the keyboards they have in the middle ( lots of used stuff )...so played a few romplers, few VAs, even happened to have an analog synth there as well. Thing is when playing these noticed that the sound was FAR better then what they have their demo units hooked up to more often then not...traced the wires lol and all four keyboards I was screwing around with were plugged into the amp. Real cool to check the back of an amp and see eight 1/4 inch plugs going to it.