You might do a little bit of research with the Gopro Camera. It can do interval sequence shot and it looks like they will soon offer a BacPac option that piggy back the camera which can double the 2.5 hrs of battery life giving you 5 hours. That might even be more in the interval shot mode. Not sure when available but I myself is thinking of getting that camera.

See the bottom of this link
http://www.goprocamera.com/index.php...2&productid=29