Cherry Corp. G80-3000 replacement PCB with support for split keys.
Schematic and PCB are available opensource under Creative Commons BY-SA 3.0 license on EasyEDA at this link
For more informations please visit this geekhack.org thread
Make example for this keyboard (after setting up your build environment):
make gh80_3000:default
See build environment setup then the make instructions for more information.