A while back I put together a template for making iterative tools using subframes which you can see here.
IterationStation is the evolution of that including various automated portions to the tool and automatic expression creation based on named knobs.
Using an image/matte input pair you should be able to produce almost any iterative tool your heart desires. That combined with a smooth transition approach that's resolution/matte size independent can create some fairly compelling results.
You can download IterationStation here!
Slit Scan can be found on Nukepedia here!
iBlur can be found on Nukepedia here!
iTransform can be found on Nukepedia here!