Record Video for Hours - compact

depends on how long you need your final movie to be. you don't need to record hours of footage, e.g. a pic snapped every minute will do for a 40 sec video at 24fps. the resolution of the pics doesn't have to be very high for 720p (that's about 1mp, 1080p is around 2 mio pixels) - unless you want to pan&zoom with the final footage. so there should be plenty of space on a big sd-card.

maybe something as simple as a gopro with a 64gb card (or even an iphone with the right app), hooked to an electrical outlet or a big external battery will do.

 

Have you considered using an SLR with a timer on it. They do this really well. Not sure how you'll go with battery life, though, no matter what device you end up using.