That is a first for me, I have not thought of combining two baffles into one like you describe.
I will leave the math to the guys better equiped.
As for could it work - I would think so, and dividing the baffle as you describe (I am assuming a vertical element) should work.
But, how large will that baffle be? The largest I went was close to 3 feet per, and I always had 4 feet between the speakers. I cannot fathom how large a baffle you would have to live with!
Not sure either, if the vibrations would cause issues for a baffle of that size.