thats a great idea mt. garden! i was about to come on the same idea reading your post when u said it lol. but then got to thinking... would it be too violent a shake? and one would only be able to use paint can sized containers??
Paint shakers have variable speeds. My guys have one they dial in depending on what type of coating is in the can! Granted, this is a commercial set up, but... that means there's used equipment sooner or later.
Tool pools work well under the right circumstances. Everybody in the pool needs to be reasonably mechanical or at least responsible, and one person needs to be the "keeper", but when they work, it's very cool. Just home from a neighborhood water co-op meeting. We designed a common water storage and treatment system, got it approved by the county, installed them to site specific conditions, buy in bulk, share water testing equipment, etc. We set it up 12 years ago to beat off developers, and it's as solid today as it was before the market dropped out of real estate!
Perhaps at the 4/20 gathering this can be a topic! There are enough of you in a relatively close radius to do some good things. I'll try and remember to bring our "paperwork", cuz 12 years later we all agree it's still perfect. cheers, mg