The only thing preventing me from grabbing either the G1 or the MyTouch is the fact that T-Mobile is the only sold service. They're much more expensive than other similar providers, and they have no 3g where I live, while most every other carrier does. Is there any way that I would be able to swap out the SIM card and us the 3G/2G networking of that carrier on the G1? My idea is to buy one off Ebay, which would come without the plan, and then slap a Sprint or AT&T sim card in it. Is this possible?