Slide show pan/zoom for museum computer screens: advice needed

For my show at the Aldrich Contemporary Art Museum, I would like to show a continuous looping full-screen sequence of about
200 slides that are panned and zoomed. The images will appear on a wall-mounted Apple Cinema monitor integrated into the show.
We need the ability to specify for each image the pan/zoom path, as well as the time the image appears, along with a simple
dissolve. Nothing fancy needed. No chartjunk should appear during the slideshow. This should run on OSX.

We are currently playing with the OSX screensaver (which works fairly well) but need greater control over the pan/zoom/dissolve of
each slide. Aperture and iPhoto don’t appear to give the necessary controls.

I would be grateful for any advice.

Thanks, ET