Here's one I found that takes 2 AA's.
Handy to be able to slip into your pocket if you're imaging in a remote location.
http://www.ebay.com.au/itm/AA-Batter...#ht_4755wt_902
This one is more high end and the batteries are built in.
http://www.ebay.com.au/itm/10000mAh-...#ht_3927wt_891
But I would still want one that I could just slip fresh batteries in if needed.