It might be a bit early, but I had that in mind when I was playing with this enclosure - the Rambo is very squeezy - the jackpot will fit easily.
I’ll be finalising the finer details over the next day or two, but basically the modules are printed in any width to suit the space you have and just slip over the tubes until the space is filled (not helpful when you have your beam assembled! 
)
I have a couple of “hole” modules to allow cable access, but need to check the clearances on the controller mount.
Speaking of which - how will you go for cable length if you mount the board in the centre of the beam? If you have a controller connected you will end up with a lot of dangling cable I think.