If you look at the example of the ryubin page - it loads instantly. The video is being streamed - so its not so bad I think. With flv files we no longer need to wait for the entire video to download before you can begin.
Also, I agree rendering 6 times the amount of data sounds like a lot of pain... but that's one of the reasons to create the community renderfarm... and Dandelo's underwater sequence - was taking me only 6 mins a frame for regular. So I think I can handle 36 mins and maybe a shorter animation. we will see...
need to make sure it has interest in all directions... Keen to do some obj replacement too... Hmmm