PyPI is intended to be an index of metadata that is generated by distutils. I'm not sure I'm comfortable extending that scope to include actual code fragments. It would confuse the meta-data schema and user interfaces considerably.
Having said that, PyPI now has a reasonable user database which could be useful to you. Code like the Trove handling could also be useful. I've always wanted some form of comment / rating system for packages too - and that'd be essential for a code fragment database.
Finally, PyPI is bordering on being too large for the technologies it's built on; sqlite will need to be replaced by postgresql some time soon and the cgi.py-based web ui scales very poorly. Development such as you're proposing would push those technologies over the edge :)