Matt,
Look into SunTouch heating under the tiles. Tiles stay cold in the winter,
http://www.suntouch.com/
I had this installed duringa recent masterbath remodel. Getting up and walking onto an 83 degree floor at 5:30 am in the winter is a nice thing. The thermostat is programmable. Make sure you run the matting on both sides of the commode too. I believe I ordered from WarmYourFloors:
http://www.warmyourfloor.com/suntouchma ... idths.aspx
I used a guy that I'd recommend for the standard work: custom shower basin versus a prefab one, tile shower and wall work, and tile floor work. In hindsight I think he way overcharged for the installation of the heating element, though.
Dan Underwood (Underwood and Sons)
336-227-5250
-A little hard around the edges but he showed up when promised and did good work. He was recommended to me by a co-worker and I have since recommended him to other co-workers.
Chris