Small update:
I now have full control of the G37 instrument panel/gauges using the CAN bus!
When I get 370z CAN bus logs, I will get it to work on the G37. If needed I can make up "translation gateway" to resolve any non-functional gauges.
Down the road, I should be able to get the 350/370 gauges to work with any other engine/ECU (VR, LS, HR to VQ, etc)
The 370 gauges are a little simplier to use, as they connect directly to the CAN bus. On the G35/G37 the "Unified Meter & A/C Amp" connects to the CAN bus and uses a serial connection to control the gauges.
Here is a before and after picture:
