Hi there! I'm pretty sure there will be. Considering how many features a modern smartphone can support, the battery drain is just something that we should take for granted until someone invents a completely different type of battery.
I personally am quite sure that Mugen Power will be offering something some time after the official release. They all ready offer a 3,600mAh extended battery for Droid 3, just Google
HLI-XT862XL and have a look for yourself!
Spelling errores aside, it's one heck of a battery.
