Do several rooms like the ones you're talking about.
1. If the powered speaker(s) will take an extension, I use a non-powered Hot Spot on a mike stand. An ohm dial lets you adjust the volume to your needs. Carvin has a nice near field non-powered small monitor for around $75.00 or $35.00 or so less than the Hot Spot. Good quality, but no ohm dial...less flexible-volume-wise.
2. If there is no way to power a Hot Spot, I use a little Roland CM-30 powered monitor. It fits on a mike stand and is the ideal small powered monitor when you need one. Lots of adjustments for sound. Better, in that regard than a Hot Spot.
That's the way I handle situations like this.
[This message has been edited by captain Russ (edited 07-29-2008).]