This is a mad endeavor.
Of course, this is the place for mad endeavors, isn't it?
Presumably if anyone can pull this off, it's the gang here.
Might be helpful to sort groups of which manufacturers still have hard numbers, and which don't, and for the latter, figure out the numbering scheme for each, and then do some leg work.
Sounds like fun.
If each of the armories tackled their own slice of the pie it would make for a more manageable task. Maybe have a stickied thread in each for that purpose that could be updated with data?
It would also help the search to evolve beyond simple random postings of serial numbers. Once a general upper register is determined, the APB could be put out for a number above #######, etc., and we needn't worry with all the clutter of collecting the in-betweens.
It could certainly serve to add another layer of detail to tools like Vintage Rex, for instance.