We have a garmin Aera 550 as VFR GPS (as a backup to the 430). This is wired into the aircraft power through a CB and has a hull mounted antenna. It is mounted on the Garmin aviation mount which is screwed to the throttle quadrant behind the levers and the wires are routed behind the plastics and carpets to it is a nice installation. To remove the Aera you pop it from the backet and take it home. However the bracket is permanently mounted to the throttle quadrant plastics with the wires permanently routed. There is also a data port mounted in the dash to connect to a Zaon as well as USB.
This is signed off by an FAA IA on a 337 so I guess should be legal? (it was installed by an avionics engineer and our maintenace co. so don't worry about fouling levers with the wires, it was done properly).