This sounds super cool, and pretty much what I'm guessing it will be (if anything at all). But, I'd be lying if I said I could completely wrap my head around how they'd rationalize this to a perspective buyer.
But the idea of a young Clark Kent in the 40s watching the exploits of Wonder Woman and the JSA while he secretly helps his town as "Superboy" in one timeline, and then a grown up Jon Kent taking over the throne as Superman in another timeline sounds like a lot of fun.
That may be part of why DC allowed Bendis to nail the main timeline down? Basically lets them say "that stuff is over there." I dunno.