I think that too long a clip in the wmv/mpeg formats may be too much. Going to take too long to download those clips. If we're talking flash, then a minute long clip could be ok (as long as the webmaster has enough sense not to give away the goods during that minute, keep it like 40 seconds of teasing + 20 sec action ending in a cliff hanger
). It wouldn't be like a tube site as you'll have one movie per page, with more ads and text around it and still within the FS structure.