Well, the newest WHQL nvidia drivers are actually 285.62 but these introduced some sort of playback issue with other software programs that required the beta hotfix drivers 285.79 to fix.
Figuring the issue to be related somehow, I've waited until the newest beta drivers were released (yesterday the 290.36).
The drivers I listed are just ones I have sitting around: Nvidia introduced a completely different issue with their drivers which mean I have to keep reverting to 275.33. I figure if they ever fix this widespread "TDR" issue they have in newer drivers, I'd like to nail down this issue I have with bsplayer too.
It seems specifically that the 285.62 WHQL broke video playback in Windows Media Center and Windows Media Player for many people:
NVIDIA 285.62 WHQL No Video in Windows Media Center - NVIDIA Forums
This only suggests to me that they are playing around with the settings and perhaps some adjustment made in the drivers since 275.33 is no longer compatible with the specific way I am using bsplayer.
If anyone with an nvidia card (preferably 400/500 series, I use 560ti) could confirm the same black screen on one surface when in dualscreen with internal renderer and aero disabled that would be useful in itself.
Cheers.