In response to your questions, yes, I meant to say MPL version 0.91.2.
I believe the objects were lists and dictionaries, and they appeared to be related to plotting parameters, such as those found in rcParams.
I'm now including a link to a gzipped tar file that includes one instance of the sample data, and the input file slicer.dat, that will have the program use this sample data for 512 iterations. The plots will appear in the plots directory, but will be overwritten each time. I checked briefly, and I believe the memory usage problem remains with this variant, as the main code itself has not changed. So long as the OS doesn't cache the data files, it should be nearly identical to running on the original data.
Just unzip and run 'slicer_mpl.py' with the optional argument of slicer.dat.
Hopefully that works for you. Thanks again.