2012-05-09, 00:20
Seems like you are reinventing the wheel here. Projects like maraschino already have great web interfaces and can control xbmc remotely (shutdown, startup, everything you wanted). it will also run on an unraid server. Worth checking out before you spend too much time on your own implementation.
http://www.maraschinoproject.com/
http://www.maraschinoproject.com/