I've dealt with probaly about 25 Sonance 1260 installations w/ 1 DOA and 1 unit dead after about 2-3 weeks of use. The unit operates at a reasonable temperature. I think that the chassis is sort of large.

... 30-40 Elan Z661/Z660 amplifiers w/ no failures that I can think of other than situations where speaker loads were too low or clients blew then from playing too loud. The unit is very fragile (in that you can't accidentaly short the outputs and expect it to work or run multiple speakers of a single channel in parallel) and runs very hot, but is very small. It is also only a 6-ch amp, so you would need 2, but having the channels split among 2 amps might be a good safety measure.

For the Sonance, gain adjustments are on the back of the amplifier via small knobs, while the Elan adjustments are in the front behind a hidden strip that must be adjusted with a small phillips driver.

I believe that both of these amplifiers run in class AB, although musical, tends to be inefficient and creates alot of heat. You might want to consider a pro audio piece such as a Crown or Crest amplifier and run it through a high powered speaker distribution unit.