Mick, you can run a seperate mixing board into it, and control it from there.
So a 5-piece could do it, and, depending on the guy running the board, could sound great.
I think that the instrument and vocal seperation would be just fine..
All ears would be hearing the same mix.

You would need a sound man though, preferably one who is not sleeping with a band member, and who would like to hear the bedmate over the others! *BG*

You don't need a monitor because the sound source is behind/beside you on stage, but if one bandmember wants to hear him/herself over the others that would present a problem; obviously because that person would want to be louder in the mix.

You guys would need the subwoofer which is surprisingly small and light.

dwd, I agree with you on just about everything, but I have seen Mick's band, and there ain't no way they're gonna do bluegrass style round one mike.
The choreography with the hammer dulcimer alone.....*G*
And dwd, there are a lot of Bose bashers out there who've never used them.
As a fultime working musician, I want small, light, portable and powerful equipment, so the Bose will do until they come out with a pocket-sized PA system that can fill a 500-person tent at a festival, or a small theater, or Elks lodge, etc. etc.

Seamus