Motion Control Camera

I originally posted this at the O'Reilly forum for Make magazine, and
was told to come here for comments and suggestions:

DIY motion control camera!

I loved the steadycam project in the first issue, but I can't help but
wonder if there is also a DIY solution for something like a montion
control camera. The basic idea of the motion control camera is
shooting the exact same pass multiple times and then overlaying the
passes to create various effects (ie. the multiple Kylie Minogues in
the "Come into my World" video or the band members of System of a Down
intesecting each other in the "Chop Suey" video).

Generally these things are attached to huge crane rigs and have some
type of computer control, but I'm thinking of something that would be
more on the scale of a table top model for a stop-motion project.

Is this DIY feasible? If so, write it up for a future issue. I want to
build it!

***

Any suggestions or advice on making this camera would be greatly
appreciated.