The highest speed is really a sham, because the film is fixed around the periphery of the camera and a spinning mirror projects the image on the stationary film.
Add to that a high speed (electro-optical) shutter and you can get mayye 24 frames at 1 million fps.

The high speed camera here http://homepage.mac.com/andreaspape/...503/index.html is tantalisingly close, in fact it looks just like the descriptions of the rotating mirror design.
See the array of projection lenses and mirrors around the centre?
See what could be a film locator around the circular housing?
I reckon this is a high-speed explosion imaging camera.

Alternatives that use travelling film and swept image projection are somewhat slower, but can obviously work for a longer period.
The hard parts are getting the film up to speed without wasting it all, keeping running speed constant, and synchronised with the spinning shutter (or prism), and managing the output film.
Come to think of it - it's all hard

These are what we're after:
http://www.lanl.gov/news/index.php?f...&story_id=6875
http://www.lanl.gov/news/index.php?f...&story_id=6895

It might be in here http://www.si.edu/archives/ihd/videocatalog/9531.htm

This is a good link too http://adsabs.harvard.edu/cgi-bin/np...e=HTML&format=

Some interesting first hand accounts: http://www.abqjournal.com/2000/nm/pa...st09-19-99.htm

And Popular Science has good stuff on today's cameras:
http://www.popsci.com/popsci/science...ccdrcrd/2.html