A 60% keyboard with a symmetrical staggered layout, sold by CandyKeys.com.
Keyboard Maintainer: Baris Tosun
Hardware Supported: Katana60 PCB v1, Teensy 2.0
Hardware Availability: CandyKeys.com
Make example for this keyboard (after setting up your build environment):
make katana60:default
See build environment setup then the make instructions for more information.
There is also ongoing discussion for the extend layer, at the Colemak Forum