I had the same concerns about wattage when I wired my remote speakers. Initially I found the Niles HDL6. This is only a switch (no volume control), so I picked up a Creek OB-8 passive preamp to handle volume control. This worked ok but the volume was the same on all the remote speakers because the Creek was in-line with the switch. Now I'm using a Russound SDB-4.1. It's rated at 200w/channel RMS and 600w/channel peak. It supports dual source inputs and has 4 outputs with separate volume control for each output. Each output channel can be set to 2, 4 or 8 ohms using jumpers inside the case. I've had a pair of these for more than a year without any problem. I got them at www.hifi.com for $299.00 each. One caution -Russound makes a SDB-2.1 (2 outputs at 100 watts RMS) and a SDB-6.1 model (6 outputs at 150 watts RMS). The SDB-4.1 has better power handling than both of those. Good luck with the hunt.
David
David