we do this all the time down at our place. in fact, i prefer it this way! love you live!
what works for me placement wise as a starting point:
drums: stick the drums a few feet out from a corner... facing
into the room. make sure the reflections from the walls aren't too bad...do an X/Y or mono mic over the kit and mic the kick an snare. more on the overhead in a sec...
bass amp: stick the bass amp in front of the kick drum pointing away from the kit. balance the bleed into the overhead, the drum bleed in the bass mic and how well the drummer can hear the bass. a packing blanket comes in handy to drape over the amp to control cymbal bleed. facing the amp itself away from the drums provides for a natural gobo so believe it or not - the bleed from the drums usually isn't too bad with something like a 421 or a 57 a few feet from the drums. the bass bleed into the overhead needs to be clean though so don't be afraid to get closer to the drums. sure, you can do a DI.
guitar amp(s): pointing near/into a/the corner(s). for two make each equi-distant from the drums. the amount of bleed into the drums will be the issue so starting with the same distance is a cool way to start. again, the amp(s) themselves will act as a natural gobo...a packing blanket over the amp (providing for ventilation!) can help as well. you'll be surprised how little bleed a mic like 57 picks up in this scenario! getting 'em off the floor is always a good idear too...
have the band play so/until they can hear each other well. if they're a practiced band - this ain't hard. now think of your drum overhead as your reverb/ambiance. this mic will have the most bleed of any mic in the room. all mics are different in the amount but the point is to use this bleed to your advantage as yer probably not gonna kill it...if you have a good figure 8 like a coles you can come surprisingly close...
oh - a packing blanket on the kick can help as well...
pardon the lame drawing but see the attachment for room layout with directional arrows...hope it works...
have fun!
Mike