I ended up buying and installing the following:
• Audiosource AMP 100 (dual stereo source, dual stereo output, 100W) -
http://www.audiosource.net/amp100.html (~$110)
• 50 watts RMS per channel power amplifier with complete custom installer feature set
• Bridgeable outputs for 150 watts RMS total output power
• 2 stereo inputs with automatic priority override, and one auxiliary output
• A, B, or A+B Speaker Selector Switches
• Front-panel mounted Volume and Balance knobs
• Manual or Signal-Sensing Power-On
• 5 way speaker wire binding posts for bare wire or Banana plugs
• 50 watts RMS per channel into 8 ohm loads with .02% THD+N
• 60 watts RMS per channel into 4 ohm loads with .02% THD+N
• Maximum 8 ohm stereo output power at 1% THD+N: 60W
• Maximum 4 ohm stereo output power at 1% THD+N: 75W
• Maximum 8 ohm Bridged-Mono output at 1% THD+N: 160W
• Input needed to reach full output: 1.4v
• Frequency Response: (20Hz-20kHz)+1dB, -0.5dB; (5Hz-65kHz)+/-3dB
• Signal to Noise Ratio: 107dB (A-Weighted)
• Dimensions: 2.9"H x 16.5"W x 9.25"D
• Weight: 9.6 lbs
• Power Consumption: 500W
• AudioSource IC8S Round Ceiling Speakers –
http://www.audiosource.net/ic8s.html (~$77/pair)
• 8 in two way 100 watt speaker (28Hz to 24kHz)
• 25mm (1in) pole mounted swivel tweeter
The speakers installed in a breeze (about 10mins each not counting running wire in the attic) in the ceiling as no brackets were needed (they hang/latch on the drywall).
Everything works really well and sounds great!
Note: After installing the AudioSource AMP-100 I realized that it doesn't do exactly what I thought it did: It does have 2 independent stereo inputs, but it only amplifies 1 stereo channel. It will select 1 channel over the other (I think ch1 has priority but I can't recall). This is kind of a bummer as for 2 independent source audio zones I'll need a 2nd amp, but if I don't mind playing the same source in 2 zones at the same volume this will work fine.
I'm still on the lookout for a decent priced multi-source amplifier: one that will amplify and output 2 to 4 stereo sources. I've seen some high end ones but they start at $700 or so.
Tim