The Nintendo Switch in Handheld mode is a keyhole controller middle. Hori's Daemon X Machina grip controller, launching in September in Japan, is a more literal interpretation of the concept. Update: And now there's a North American Amazon listing for it.
The Grip controller is pretty limited. It does not have an internal battery, so it can only be used when attached to the switch. It's got no gyro sensor, infrared camera, NFC communication or vibration. What does it have is chunky buttons, large analog sticks, a proper d-pad and what looks like a nice folder.
Hori uses the extra real estate on the grip controller to add a programmable button on the back, which can be mapped to any other button on the controller ,
And for extra attack power in Daemon X Machina the mech game the Grip controller was designed for, the controller has a turbo feature that allows a button to activate five, ten or twenty times when pressed.
Da Mach X Grip controller is coming to North America. It goes on sale in Japan in September for around $ 45 USD, and there's always the option of importing one, if you really want to switch to this huge.
Update, 9:00 p.m. Eastern: out by Wario64 on Twitter there is now a pre-listing for the Hori Switch Split Pad Pro on Amazon.com. It costs $ 49.99 and will release on September 30.