you owe it to yourself to check out http://www.fookes.com for easy thumbnails. tom your life is about to get wayyyy easier. I've used this for a couple years now and find it awesome - especially for creating video from SU.
Output animation as huge jpegs from SU, then thumbnail them to the appropriate size in a batch - takes no time at all with this app, then use virtual dub to create animation (avi) from the jpeg series... cut in some audio using Atmosphere deluxe (thanks to Alan Booth on that one!) and presto!
Shaun Tennant