My proposal has 9 jacks, 5 pots, and a switch, in 10HP. Only one pot (the crossfader) is regularly adjusted during performance. The layout should give the crossfader a generous amount of room, free of jack connections.

This proposed panel seems generous compared to many existing modules. For example the WMD ALYS has 14 jacks, 2 pots, and a switch in 6HP. What I am proposing is actually more roomy. It will be easier to use for reasons of space and because it doesn't include unnecessary features. The whole point of this thread is that I don't wish to use the three cramped modules mentioned in the OP.

Larger mixers all have features that are inapplicable to the application I have described. That is because they are not designed for cross-fading two (and only two) stereo streams. Hence they waste space. (For other applications they might be fine.)

I have already clearly said that because of my physical disabilities, I need to limit the size and weight of any rig I carry to a gig. This is hardly strange: many other performers have similar requirements (even if for different reasons). The lack of understanding here is perplexing.

OK, maybe 64 HP will be too small for the music I wish to make. Who knows? But that is also irrelevant to this thread. Because no matter what size the case, I don't wish to waste room on functions that are simply not needed.