Fair enough, I've never used the coax box, but it did get heavy use in my son's room when the 630 was new. I ran coax and four pair copper from the cable box/VCR and computer setup in our bedroom into his. A Radio Shack IR repeater let him control either one remotely from his room. So I guess it has some sentimental value for me after all.
Neat setup. At first glance that coax box and the additional height it imposes on the assy gave me the willies. It makes your box really tall and thin in its aspect ratio, adding 4" (more like 3.25" IIRC?) of "knock over lever." The only thing I can think of if you want to keep it in your spec would be to let it define the width of the assembly instead of the height. lay it flat underneath the PSU and you can spread the rest of the top section across the front and back edges of a 4" shorter and what should be less than a half inch wider box? If tall and thin with a centered CF slot is your thing, I'll bet you can squeeze the coax box in above the mobo to reduce the box height/knockover force amplification of your MicroQuadra case without adding any width.
Make some cardboard case prototypes and paper internals boxes to play with the mobo and blocks in 3D.
edit: just thought of this, you're not wedded to positioning that box on the backplane, you can place it anywhere you want to and crimp a custom male to female panel mount F-Connector coax cable anywhere you've got a convenient space for drilling a hole for the connection breakout.
Edited by Trash80toHP_Mini, 04 August 2017 - 05:28 PM.