I've had great luck with the Sony W230 cameras paired with a Yeticam.com control board. I also love the Sony HC40 MiniDV camcorder. They will run for 5 weeks with a big battery. The quality is great for standard definition footage. National Geographic purchased some of my elk footage for an upcoming Untamed America production.
I also have a Sony XR550V HD camcorder that takes unbelievable footage. But it's a lot of money for a camcorder to strap to a tree.
The still images I've posted on the main page of my site:
Off The Pavement convinced me why it's worth the time to learn how to build my own cameras. I hope this is helpful.