I would love to have a complete python parser for the metadata. I strongly recommend collaborating with the Gutenberg package posted to HN a few weeks ago (and his rdf branch):
https://github.com/c-w/Gutenberg/tree/migrate-to-rdf
GITenberg has a mailing list and would love to have you!
I was looking to write an alternative search for Gutenberg, based on the RDF dump, so would be happy to collaborate/discuss ideas.