OK I was at the meeting and I am a low budget filmmaker and a a recent new member of BECTU.
I think there is nothing wrong with having low budget movies use a collaboration, like carving up a pie. Obviously the director, producer, heads of departments, DOP, camera operator, sound recordist and the runners will get different size slices of the pie.
This might be dealt with by having a maximum or minimum share anyone in the project can get. What about investors? They usually want at least 50%.
Then you need to work out is it a gross or producer net profits pie (eddie murphy quote "monkey points"), the problem being if you carve up a project into gross points no distribution or sales agent will touch it.
There is a good book that deals with collaborative film projects "Feature Film Making at Used-Car Prices: How to Write, Produce, Direct, Film, Edit, and Promote a Feature-Length Film for Less Than $10,000 by Rick Smitt".
I think the other thing you would need to do would be figure out what kind of budget this might be appropriate for say below £50,000.
Make it a code of practice, but not mandatory. There should be some reason that would make it easier for low budget filmmakers to use this such as standard simple contracts that everyone understands.
Then get Equity to accept it, Post production houses, and the music industry to accept it too.
The only problem is getting them to believe that there will be any profits.
Well if someone works out blueprints for how it might work, then someone else . ie a low budget filmmaker will have to try it out to see if it works, I hope they get a grant from somewhere.
I still think the problem is filmmakers, getting little or no money for films once they are finished.
For more information checkout Chris Jones blog http://www.chrisjonesblog.com/2010/03/bectu-debate-and-the-national-minimum-wage-lets-all-throw-stones-at-each-other/comments/page/2/#comments