I was thinking one of these
I bought and use one of these:
http://www.amazon.com/GreenWorks-20362-10-Inch-Cordless-Chainsaw/dp/B00LK2MGEA
It works great! I can easily cut 3-4 days worth of wood (not building bonfires or anything, though) before the battery runs out. I sharpen the blade before each trip.
The only problem is that the oil reservoir is kind of leaky. I transport it inside a garbage bag, and don't put oil in until I arrive at my site.