Similar to the PocketCHIP "Mechanical" Keyboard I've designed a hinged key faceplate that can be used standalone or mounted in another project.
Here you can see the PCB mounted using small self tapping plastic screws.
The keys are held in place with straitened paperclips. Music wire would probably be a better alternative. You can see where the paperclips are inserted on the edge of the faceplate above.
Here is the front. Keys have inkjet printed avery labels on them, nothing fancy yet. Font for the legends is https://github.com/be5invis/Iosevka