In Japan you can now buy this gun styled grip for the Olympus Open Platform Camera (OPC). Use at your own risk.
The OPC is a camera module concept with an interchangeable Micro Four Thirds mount that was announced during the 2014 Photokina show. You can see the best solutions for the Olympus Open Platform Camera on this dedicated website.
The Olympus AIR is based on the OPC and is currently available in the US.
Few months ago there was also this “rocket launcher style setup” based on the Olympus AIR:
