One amplifier which really impressed me (in the store) was a Fender Keyboard SFX 200. This single box amplifier produces stereo sound (2x80 Watt), and the depth of stereo field is amazing. Normally, you need two speakers to do that. It is not very small (though seems to be a lot lighter than my Peavey KB300), and costs $650, but for small parties or home it would be great (I'd get one if I was on the market for an amp).

The other option: I received a Carvin catalog, where they advertize an amplified speaker with 10" woofer, built-in 4 channel mixer with separate tone controls, 100 Watt of amplification, weight 37 lbs, and works from AC or built-in battery. The price for one is $500, but they also offer it with an additional, unpowered speaker with matching acoustics for $550. For a small light setup this looks like a good deal.

Regards,