This looks really great.
Are you going to be creating this as a commercial product? If not (or even if you are, but are able), I'd love to know more about this and how you are tracking the viewer. I would think it especially difficult to implement since you must change the views and renders independently along both axis for the stereoscopy to work correctly as opposed to having the offset along just a single (horizontal) axis for displaying on a wall where you can assume the viewers eyes are horizontal.
Are you using your own renderer for this?
As for your question on plasmas, I think that Cyber may be right since the HDMI spec usually only accepts 60Hz input Max. On the other hand though, if you use TV glasses, I believe they are 120 Hz usually so you should be able to just render at 60 Hz per eye and the TV should double this when it's displayed which is the requirement.
240Hz or more may be pushing it though. The plasmas may have sub-field refresh of 400 or 600 Hz, but I don't believe the processors will actually be displaying these as unique frames, but probably refreshing at that rate from a high speed frame buffer. Maybe someone will correct me on this though.