All iPads: Which Cellular Model has Best Resale Value?

[BruiserB]

Planning to get a wifi + cellular iPad mini. I want the cellular primarily for the GPS capability and probably wouldn't activate with any of the cellular providers. I might try to use it on T-mobile, but understand that both ATT and VZ units will work for sure on T-mobile's HSPA+ (not LTE)....not 100% certain of Sprint one.

Thinking forward to when I may go to upgrade in the future, is there one carrier's model that would potentially have better resale value? Would it be the VZ one since they have more LTE coverage in the States and thier LTE frequencies match up with European carriers? Also if I never activated the stock sim card from VZ could that have future value since I understand unactivated prepaid VZ sims are hard to get? I've read the ATT one's LTE frequencies match up with what T-mobile will eventually roll out, but I'm thinking that even if I do use it on T-mobile, I will probably upgrade to a newer iPad by the time they get around to rolling out LTE.