Nice! That looks like it's as small as possible while still having 3 CIMs and PTO.
How do you plan on mounting the gearbox? I see 3 holes near the bottom, but 2 of them are #10 screws that also have to go through the CIM, and the third looks just a bit too high. Maybe you'll have to make your gearbox plates slightly larger for more mounting points.
Assuming this is for WCD, how are the sprockets going to go on? Mostly I've seen them inside the gearbox, and that would make this gearbox wider. I guess your gearbox is
too small!
How do you do the hex sleeve thing for the output? I've heard to mentioned before and tried to imagine it, but what's the "normal" way of doing it?