I was googling around for some unrelated project, and I bumped into MakerBeam. These are very similar to the standard 2020 rails, except they are 10x10mm with a m3 rail. And the best news is, they are pretty cheap! I’ve seen vector rails go for as much as €50/m, this stuff runs around €7.50/m.
The fit for Kosmo modules isn’t perfect obviously, it will leave a 2mm gap above and below your modules (4mm between two rows). I wouldn’t consider this a big problem. Maybe it’s even a good thing, as homegrown panels tend to have pretty wide tolerances. It also comes in a black anodised finish, to the gap won’t be nearly as obvious.
I haven’t designed my next case yet, but I think I will try out this stuff!
Small gaps can be very useful.
Dupont headers and cables can provide power or a breakout for vactorol control, passive mixers, sync or test points for a meter or scope.
Embed LEDs for a cross case Vu meter.
Mounting some discrete patch cable management or a point to temporarily mount some external fx.