It's a noble idea with great intentions, but will be nigh-impossible to pull off.
I don't know your GB experience, but in most GB's every modeler is working at different schedules due to life responsibilities, motivation, skill, tools available, etc. etc. There are many who sign up and then disappear completely. So actually getting a group of modelers to build at the exact same pace for months on end will be akin to herding a bunch of cats with ADD. Without actually seeing the cats.
But that's just my .
Cheers!