I get these as a digest so sorry if someone's already
spoken to this.
Laurence Pearl wrote some code to interpolate between
scenes as you describe. Kristian Rother wrote a very nice
set of framework commands (and more) to make movies. I
wrote an extension of Laurence's commands so that they
would fit better with Kristian's commands, which I was
(and am) using. So...I had mailed this to the list some
time back and it should be in the archives if you search
for the "movie" or "MasterMovie".
But really, it should go on the wiki, of course, and I'll
try to get some time to post the most recent one there
soon. I think some version of this also exists embedded
in Kristian's rTools.
I also keep wondering if Warren is changing how the camera
is moved in the vein of being able to do this more
internally to PyMOL?