Hey, I have buy these aluminium rails and there are perfect for our modular cases !!!
I have payed 7€ for 80cm.
(~7$ for 31,5inch)
Here the shopping links:
Aluminium rail =>
M3 sliding screw connectors =>
M3 screws =>
Hope this will be useful for you !! 
Only IF you leave enough space at the top and bottom of your modules…
You have to plan your modules with that in mind.
“Standard” Kosmo modules won’t work with these rails.
Yes I have 2cm in top/bottom for each rail… I use 17cm for my panels format.
How is the format of kosmos ?
20 cm.
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!
A 4 pack of 60" Vectors sells on Amazon in the US for $82 which I think works out to about €11.5/m. Coincidentally, a 4 pack of 2m MakerBeam is also $82 which comes to €8.75/m.
You have to use M2.5 slide nuts with Vector. Do threaded strips or cheap M3 slide nuts work with MakerBeam or do you have to spring for their t-slot nuts at $16 for 50?
ah, I must have been looking in the wrong places!
From what I have gathered, hex m3 nuts or the square m3 slide nuts won’t fit the makerbeam profile, so one will have to opt for the dedicated slide nuts, which are, admittedly, pricy.
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.
No problem for me, I use only this rails with M3’s screw/sliding nuts…
work very good and really economical compared to Eurorack equipments !
They need 2cm free at the top and 2cm free at the bottom of the panel
is that makerbeam? Looks awesome! What kind of slide nuts do you use? The makerbeam ones?
take a look at links of the first post, this is what I use. 
20 x 20 mm, so for Kosmo modules with mounting holes 194 mm apart that gives 174 mm clearance which is just slightly less than the figure mentioned in the spec discussion:
In practice I’d guess most Kosmo format modules would fit.
Definitely too wide for Eurorack. Personal or other formats, you do the math.
US price is $14/meter for 1 m lengths, plus shipping, and $2.34 for 30 t-nuts.
Ah you’re right sorry, missed that.
I know I have some which barely fit the 180 mm clearance I currently have, so I’d be hesitant. 
