Well, I've had a bit of a hack this morning on the train and a little bit more on & off during the day, and I've worked the Trove discriminators into the database schema. I've also written the migration script so we don't lose the current submissions. I'm part-way through working the storage layer to handle the new code - the good news is that most of the upper-level code won't care about the storage changes. The new packages and releases tables split (from the original single packages table) is easily joined to provide the old view.
I've moved over from using the rfc822 module to the new email package shipped with python 2.2.2, which instantly fixes a problem one user had with multiline Description: fields.
The PEP has been updated too - more tomorrow when I finalise the database schema. I figure there should be some mention in the PEP.
I hope to get the new version out tomorrow. Fingers crossed...