I've got one working for the 704 Wifi...same screen resolution. I've been using Mencoder to convert to a 720x480 XVID after finding and cutting out all commercials. Not sure if that would meet your needs on the speed front (probably around 45 minutes).
I'll try to tinker with Avivo tonight and see if I can get it to work. Does anyone know offhand how Avivo handles corrupt video or audio (ie a reception issue in the middle of a show?)