I haven't got a model A yet but I was tempted to get one to see if it could run as a simple orbiter combined with the small adafruit touchscreen and placed in a wall box to control lights, set alarm status etc.
Not sure if the 256mb ram would run orbiter though but a web interface may work, I know this could be done with the model b but this a+ is quite a bit smaller now and more importantly in-wall its not as tall.
Just my ideas there so cheep you can afford to experiment:)
I have run orbiter on an Adafruit touchscreen. The screens are much too small to be usefull as a full orbiter, a minimal version *could* work but that is a lot of effort. Running a weborbiter or something similar, as totallymaxed suggests, is likely the best option for the A+.