After a five day outage a few years ago, I went with a whole-house Generac -- 15kw, auto cut-over switch, etc that is large enough to run everything including one AC/heater unit. I've never noticed any problem running any appliances, but then again I don't have a plasma so I can't speak to that. We don't have natural gas in the neighborhood, but we already had a 100g propane tank buried in the back yard. This will last us about 50 hours of continuous use, but we've stretched it to last almost a week by running it a few hours at a time to make sure the water stays circulated/skimmed enough and the upstairs stays warm enough. Total cost and installation was just under $5000, but we were putting an addition on the house at the time, so we just rolled it into that cost. As for a shelter for the switch, I'm not sure what you mean, but for us it's just another panel that gets mounted to the wall next to the existing electric panel.
If it makes it any easier, just consider that it is a true capital investment for the house. I'll never have another house without one in a neighborhood with above ground power lines :-)
Matt