MarcK,

I don't know what the audience hears, but I agree with Donny, that the first person who must like the sound is myself - when my music sounds good to me, I can entertain my audience better, even if the audience does not know the difference between mono and stereo.

As for one-box setup, I have a Motion Sound KP100, which I am considering selling (and just sticking with my large system). The KP series of Motion Sound is designed to reproduce stereo sound from a single box (I am sure you can find many posts here on this topic). I find that my gigs are mostly in front of larger audiences, and most involve dance music, which is why I find that I am not using the KP100 lately.

The other single-box solution used to be Fender Keyboard SFX - really nice stereo separation, 160 watts. I heard it in a music store, and liked it, even though it was kind of expensive. Fender stopped making them, but you can still find them on Ebay sometimes. I have not heard anything negative about them, other than the fact that it is on a heavy side (but has wheels).

Regards,
Alex