The WeirdFlexButOk is a hot-swappable unibody ergo split keyboard by Penk Chen. The PCB is thin enough so it can flex to follow the case’s contour, providing tilting and tenting.
I just finished another build / PCB design. Basically a 0.8mm FR4 PCB with built-in kerf bending cuts, so it flexes and bends for tenting – Penk.
The board was inspired by Joe Scotto's handwired ScottoErgo but opts for Choc spacing and hot-swap sockets, plus a super-bendy 0.8mm PCB with kerf bending cuts.
It provides a 15° tilt and 10° tent via a single FR4 PCB.
According to Sneftel, who used a similar approach on the thumb cluster for his Gull, 0.8mm FR4 can take a 60mm bend radius without breaking or buckling "if it’s treated carefully and you don’t give it weak points" – a real game changer for e.g. keywell designs.