Which is exactly what I have done with selling my iPhone for a 3G, 3G for 3Gs AND 3Gs for 4. Its called people who want to unlock it. I do not expect to get as much for the 4 as I have gotten for the others since unlocking is somewhat ubiquitous at this point. However, I am up for contract renewal so I still expect to break even or make a bit.
Which is exactly what I have done with selling my iPhone for a 3G, 3G for 3Gs AND 3Gs for 4. Its called people who want to unlock it. I do not expect to get as much for the 4 as I have gotten for the others since unlocking is somewhat ubiquitous at this point. However, I am up for contract renewal so I still expect to break even or make a bit.