I'm eligible for the fully subsidized iphone. I don't use an iphone and I buy all my phones unlocked/off contract. I have no intentions of leaving AT&T. I usually use my upgrades to buy phones and re-sell them to subsidize the purchase of whatever unlocked phone it is that I want. I'm considering buying a 16gb iPhone5 and selling "brand new in box" w/out ever opening it. My main question is what happens when the person who buys it from me turns it on w/ the nano-SIM that is presumably in the iphone from the factory. Is that SIM already registered to my account? I don't want to have to open the box/break any seals to maintain the highest re-sale value. However, I also don't want to have some issue where my phone number/account is associated w/ a SIM that someone else has. I don't know how the iphone (purchased from Apple using an AT&T subsidy) activation works. Any info on this would help. Also, any guess as to which version would have the best re-sale value? I was thinking 16gb/black but would be interested to hear opinions on this.