Hi - Range creator (and longtime MacRumors reader) here. Thanks for the interest. We went with wired instead of wireless for reasons of reliability/cost/battery anxiety/reliability. Also, we did design it for more than just outdoor grilling.
Put your phone under a bowl and/or repurpose your old 3GS, maybe. I'm most excited about our plans for the app - we didn't want to just do some skeuomorphic temperature dial. I'm going to get to be scientific with my complex experiments using the recipe graphing!