997 Complete Power Failure - HELP!

[PorscheMikeGT3]

Could use some advice from the 997 community. I have a 2007 997.1 GT3 track car. Last time on the track, car shut down mid-straightaway at speed. When I tried to restart, the engine did not crank & the only sign of power was dimly lit back-lighting of the gauges (no icons or warning lights at all). Had to be towed off the track.

I have done the following to try to diagnose & fix this problem:
- Replaced the battery
- Checked all battery cables and grounding points
- Replaced emergency power shut down switch
- Replaced ignition switch
- Replaced the alarm module

None of this has made one bit of difference. BTW, I'm not even getting power to the OBD-II port. Has anyone else ever experienced a similar problem?? Suggestions would be appreciated. Thanks in advance for your help!