I can give you a copy of the SQLite DB to investigate yourself if you like. I haven't seen anything at this point that creates a technical hurdle
The DB is relational, which will help a bit with collection management. Thumbnail file paths are stored in the books table. I haven't dived in to try to find a pattern to Sony's own choice of where to put thumbnails. I also haven't yet checked to see if Sony uses a single DB or if it has one DB in main memory and another on the SD card.
I'm doing a little work getting accustomed to the Calibre plugin model and the existing PRS and Kobo plugins (since the Kobo plugin uses SQLite). But it is a little slow simply from lack of knowledge of the code, and having to fit it in with what little free time I have.
EDIT: Doesn't help when Bazaar isn't Lion compatible out of the box. Took me a bit to actually read the warning on that one.