It would be really easy if there was something like this but for a CTS V which would allow you to easily fit a Nexus 7 or similar tablet. Then you can run something like Timur's Nexus 7 ROM on it which will make it behave as you expect any retail double din device to. Finally, for the OEM gauge displays, Torque Pro + Widgets + Bluetooth OBDII dongle will provide a very similar experience.