This, friends, is the definition of “caught between a rock and a hard place.” You see, AT&T is desperate to hang on to its iPhone exclusivity, particularly now that Verizon Wireless is reportedly looking to coerce Apple into producing a version for its CDMA network. On one hand, keeping the iPhone close to the chest enables AT&T to net loads of new customers; on the other, it forces the carrier to continually upgrade its networks to handle the influx of data usage. A tough spot to be in, clearly.According