You also have the option to buy a phone case/battery case.
I'de certainly like to avoid making the phone any bigger than it is. I have the Otterbox on it now as I can be rough on stuff... and it's way bigger than the phone without it.
Like I said.. my battery life currently isn't too bad (that screenshot above has 1 day 17 hours of standby with 2 hours 21 minuted usage and I'm at 50% battery).