i think you might have probelms getting a good mix live unless you have alot of mic's (and channels).
main reason is the drums, say you want a kick, a sm57 on the snare, and a 57 on the toms and an overhead sm57 on the high hat and cymbals.
well, theres all you 4 imputs right there, and unless you went from there to a mixer and out one track its gonna cause trouble.
thats a small setup on drums too, alot of people in the studio setup a drum with 6-9 mics. (of course you can just do an overhead or a pair of them but its not going to be near as good of a dynamic range as you could have)
so....alot of inputs=alot of money needed for gear.