When you say "the unknown of the WVO", do you mean the uncertaintanty of where to find it? Or something else. For the amounts that a single person would consume in a home brew setup, there is still a lot of WVO to be had. That's one of the nice things about Houston and the surrounding areas. We have more restaurants per capita than anywhere in the nation. And they all fry something. For a group, such as ourselves, we wanted to ensure that we had a reliable source. We had no problem. Not really sure what a co-op would bring to the table, except to perhaps line up larger sources of WVO with contracts. The other obvious reason for a co-op is to share in the cost of the processor and the ability to buy the consumables (methanol, catalyst, etc) in bulk, thus getting a little better price.
I have no idea what some are paying for WVO. We found more than enough sources for our group free of charge.
I thought this article in the Houston Chronicle was slightly funny and some sensationalized.
Grease pirates plunder tanks of old cooking oil
http://www.chron.com/disp/story.mpl/ap/business/5792658.html
SD