Thanks to the feedback and test data provided by some excellent people (Thanks Juri, Matt and DC) I've managed to fix several bugs in py360 and it should now be a smoother experience.
The biggest fix is in the STFS parser which would naively assume that all filelisting blocks were contiguous, this fix means that STFS files with large numbers of files inside them will now work (e.g. Profiles that see a lot of use). Now report360.py should run cleanly on (hopefully) all images and the only errors you will see will be from trying to parse deleted files (they are recognisable by the ~ that precedes their name).
Next up on the dev list is to investigate the unicode parsing problems that occasionally appear and cause extraneous bytes (usually nulls) to appear in the output. Worst case I plan on changing report360.py to remove the null bytes, best case I find the underlying cause and sort that out.
If you would like to help with py360 I'd like to hear from you. I'm really interested in hearing about your experiences with py360 and especially tell me of any errors of inconsistencies that you encounter. If you're a programmer and really keen feel free to contribute code —especially example programs and bugfixes— I won't turn you away!