Now that AT&T is taking on iPhone 3G customers by the truckload, not to mention its endeavor to sell all sorts of data-using netbooks, it only makes sense to push some of that subscriber revenue back into the network. Recent reports are suggesting that the nation’s largest GSM carrier is looking to double the capacity of its high-speed mobile broadband network “in order to accommodate a slate of new data-heavy devices that may include a new iPhone from Apple.”Beyond that little ‘new iPhone’ hint — which