If you look closely at the top of the headless 45MXT in this ad, you can clearly see that if you were to remove the clamping hardware, there is almost enough room on top for the unit to sit. One would then have to either cut out the two pieces of support metal in the back that would block the box from siting flush, cut slits in the box for the same reason or make a platform that would allow the box to just clear the angles. If the light source is as big or bigger than the round opening then all I would have to do is make a seat for the diffusion box to sit in, it could stay there and not have to be removed each time I swap negs. I fab stuff out of aluminum all the time, if this generates little to no heat, I could make life even easier and do it out of a combo of black plastic and aluminum.
Ultimately, it depends on what the dimensions of the box are....
If I can get this to work...I think I am in. I would use my iPad-2 without hesitation, would love to not have to put MG filters in front of my Apo-N enlarging lenses all the time.