Protieusz published the Gerbers and STLs of his Cornball, a monoblock split based on the Cool536lc/Cornelius with a 25 mm trackball and 4 LEDs.
Specs
unibody split
3x5+3 per half (+1 center key)
MX, soldered
Waveshare RP2040 Tiny controller
trackball
roller encoder support
The keyboard is powered by the Waveshare RP2043 Tiny that has a USB-C daughterboard. The switch plate in integrated and is 5mm thick with a 25 mm trackball holder. The case is heavily modified from the Cool536lc to accommodate the trackball in the center.
The PCB has support for an optional EVQ roller encoder or a MX switch at the top center position.
Initial prototype PCBs have a weird flaw. The "Q" switch footprint somehow shifted upwards making it not fit in the switch plate. So I had to bend the 2 pins and cut off the bottom steam holder area in order to fit the switch plate. Then flux solder the pins. The PCB gerber files have since been corrected but untested since I don't want to waste money on another set of 5. Please print at your own risk – Protieusz.