I'm in the design phase for a keyboard emulation controller for gaming, it basically has 4x3 or 6x3 setup, each is mapped to a key or key-combo, the first prototype is hard coded, the next via pc software, usb based connection, the up and lower "tap" button is done by tapping vertical paddles with ya finger and you can press down on center button.
Reminds me of https://geekhack.org/index.php?topic=41422.0