you're pretty right. the xenarc I beleive works like a normal LCD and turns on and off with video signal
I'm thinking the safe way to go is to just get an Opus 150w. Do I need anything other than this to power a pc and xenarc and have them shut off when I pull the key? I've yet to pick out a motherboard but I suppose I just need to find something that stays under the amps mentioned by the opus site?