I've calculated my Arduino Uno setup to be ~2200mAh (this includes LED and some sensors).
LiPo seem to be the way to go, however the larger LiPo batteries are too bulk for this project.
This is not very clear. Are you saying that your setup draws 2.2A? So running for an hour would require 2.2Ah (or 2200mAh)?Or are you saying that you would consume 2200mAh in your desired time period?Either way...LiPo's are pretty much at the top of the list for energy density, aren't they?