I just downloaded the 2.1 SDK and it doesn’t look like it includes the Mandelbrot demo anymore, any reason in particular it was removed?
I am only guessing here but having got it working under bootcamp windows on the same mac it seems to allow hardware double precision as an option if you click the mouse correctly. It is possible that with no cards yet supporting double precision (cc1.3) under OS X (save the new Quadro) that this is one reason why it is not there (managing the mouse options itself might be another issue, as Mac only has one button!). There are several other files in the Windows distribution not yet in the Mac one.
If I get time I might move the code over to OS X side and try to compile and see what happens.