There was a scan platform for the camera on Galileo, but unfortunately the non-deployment of the high-gain antenna rendered it much less useful - all data had to be transmitted via the low-gain antennae at a drastically reduced bit-rate. I think that it was loosely based on Voyager design, but with a part-spinning 'bus'.
Cassini is much bigger, and is a one-off design, planned for the Saturn tour, carrying the Huygens probe.
It's frustrating that Cassini has the two very effective cameras, but has to rotate them away from useful targets when downlinking data to earth via the high-gain antenna. Perhaps it would have been as good to have much more data storage capability (10 times or so) and then downlink it all when out at saturn apoapsis.