Did you capture this dxdiag with the rift plugged in?
Can you provide some more information?
The output_log.txt from the _Data folder and the full dump files would help.
If you allow for an exclusively 2D mode, do you still get the crash if you don't integrate the Oculus SDK?
What the API compatibility level do you use in Unity?
If you use .NET 2.0 subset, what if you build the project with .NET 2.0?