As bandwidth prices come down you are going to see more Tube sites giving better content. For example
http://www.100tb.com/dedicated-hosting/unmetered.php , 1 gig for $599, at this rate the Tube owner only need to make 20 sales to cover his cost.
Telling Tube site owners to limit the movie size is like telling craigslist to limit their ads so the news paper biz makes money....it will not work.
All most 20 years ago I wrote a MS Dos software and gave it as a shareware. People who used it a lot and wanted it seen developed paid for it. I made a ok income that allowed me to drive a BMW while i was still in college (every one thought i had a rich dad). May be that will work on porn, people who like a given studio / type of content continue to pay for it . This involves educating the user and making him a fan. I know few studios have done a good job and got a loyal following that they get pre orders in the 1000 - 2000 dvd's even before the movie hit the street.
I developed VOD software for the porn biz for the past 10 years and I know first hand how bad sales are.
Jay
objectcube.com