I have had a similar idea in my head for a while... but my recent experience with CUUSOO kinda gave me a cold shower...
Anyway, here are the high level principles of what I had in mind:
A yearly contest around CUUSOO organized in collaboration with the major AFOL communities of the web... I probably don't know them all but I was thinking of EB, Brickset and FBTB (some kind of tri-wizard tournament).
The contest would have a theme picked by the organizers I'm not sure how but they could perhaps run metrics on what are the "hotest topics" identified on the forums.
The contest would be organized in 2 rounds... First round would be held on each separate website, at the end of this first part the champions of each community would be identified... Second round, on a separate platform, a vote between the champions of each site - the separate platform could be LEGO sponsored in order to remain "independent".
There would of course be prizes, but the grand prize would be the "commitment" of each community to support and promote the winner(s).
Why extend to other communities? Simple, we have to if we want the winning projects to stand a chance on CUUSOO - see how difficult it was to push the Western town?
One more detail, usually the contests are asking the participants to submit new MOCs, in the scope of this idea the rules would be different and participants would be allowed to give it their best shot, regardless if new or old.
If the Winchester had worked I would have offered to sponsor the prizes of the first contest with the royalties... Well, that didn't go as planned so we'll need to figure out something else but I'm sure TLG would be willing to support an initiative like this...