I’ve recently built a GeistGeist Totem. 36 keys, splayed, low profile. With silent kalhi switches.

It’s more silent than membrane keyboards, completely customizable and super lightweight. (Got a carry box that is the size of a small paperback)

You can download all the schematics (also the board) and case files to print them. The assembly requires a bit of soldering. All in all it costed me ~150€ but I printed some extra stuff to try out.

There are also places that sell kits directly so you don’t have to source all bits and pieces yourself