I am extremely pleased with the results achieved when I upgraded my nice multichannel amp theater to a mono block layout up front (and a matching stereo amp in the rear). It will help to have a dedicated power circuit for every amp in the room. I also chose to run the HT processor into a pre-amp, so that those mono beauties can double as a pure two channel system. A full range (LARGE) center channel is required to really pull all this off. A sub like the models from REL can help with the center channel size issue.
There are many high quality mono blocks available today. I assume that you are looking for solid state if the application is HT. Tube life expectancy doesn't seem to lend itself to HT setups, not that there aren't guys doing just that.
I was impressed with the Classe CAM350 when I auditioned it a few years back. Classe has since introduced the smaller CAM250. Classe may be in the middle of a model line revamp. Theta Digital also has several mono's (the Citadel and Intrepid i think???). McIntosh has recently come out with a MC501 to favorable review. Earlier McIntosh models are probably also available. Mark Levinson also has a few models (although used is probably the only way to get them for the moment...). Further down the line are amps from Bryston, Parasound (Halo), Marantz, and Integra.
I recommend listening to the Dynaudio Evidence Temptation. This is primarily because they do have a large center channel for them. I belive that a large full range center channel is critical for an over the top experience. I use a Dunlavy HRCC (bascially a squished SC-IVa), but alas Dunlavy was aquired by a third party, which subsequently closed the doors. I did find the Dynaudio's a touch bright when pushed, but I didn't have full control of the demo.
After AC power, the other two practical matters to consider in a mono block theater are HVAC (well ok, just cooling) and structural engineering. All these speakers and amps and video in close proximity will exceed 125lbs/ft2, and thus may require a little extra thought (unless you are on a slab on the ground floor).
Good luck!
