Stereo VR compatible with other VR modes?

I have an application that's implemented with Stereo VR support (OpenGL, frame interlaced).

I want to be able to run that application in a variety of VR setups. I know that Unity allows you to specify the vrmode on the command line. The problem is that if I choose None or Split (don't know about other modes), Unity still appears to create a stereo 3D window. So, while in non-Stereo modes, you get a blank buffer on alternating frames.

I'm assuming that the stereo support flag on the player preferences causes a stereo 3D window to be created. Is there a way to override that at run-time? (It'd be nice to switch between modes at run-time, but I'd be OK with setting up the mode on startup.)

[I've been able to run non-stereo by turning off the Stereo 3D on the graphics card driver, but I really should be able to run non/stereo without doing that.]