The OGC movement was begun, unless I'm mistaken, due to the success of the Open Software (OS) movement. So if you really want to do something like this then it would only make sense to model it on similar things in the OS movement.
In the OS movement three levels, for lack of a better word, of participant have been identified. There is the user who downloads and uses free software. These people contribute to the community by posting usage questions and answers on message boards and mailing lists. Then there is the contributors who develop free software as a labor of love. These people contribute to the community by expanding the base of software offered or improving current free software. Then there are open source professionals. These people both develop and use software that is free, but they make a living working as consultants and selling their knowledge of open software to companies by implementing and/or modifying open source for the businesses purposes.
This community is largely tied together through sourceforge (
http://www.sourceforge.net).
So, if you wanted to accomplish something like this with OGC, I would think the first step is to set up a source forge type site for OGC. This site would need a large support base to be useful at all. Maybe some populare role-playing site, possibly with a grandma rule, could let you leech off of their user base by affiliating with you.
Then you would have your three levels of participants. There would be the users who download and/or buy open content. The contributors who add to or improve the quality of the open content offerings. Then there would be the professionals, publishers, who produce OGC works for sale which may or may not include CGC as well as OGC.
So the offerings for free would usually lack something. Formatting may be needed. Art may be low quality or completely missing. It might be all crunch and no fluff, or vice versa. The professionals could then take these offerings add the finishing touches to make them professional quality and sell the books.
YMMV