I finally sorted out some remaining issues and released a new Jockey. This brings support for third-party package repositories, and implements an XML-RPC driver database client, aside from the usual load of bug fixes. The test suite improved again, too, it (optionally) uses python-coverage now.
Planning ahead, the next things I want to get to are
Find some interested people to work on a driver database server (I will write a specification page for it soon).
Write a driver DB implementation for the OpenPrinting driver database.
Implement a dbus service to request a device driver. For now this will be used by system-config-printer to request a printer driver, but I guess it will be generally useful for other parts of the desktop as well.
Change the upstream default implementation of the package related bits in OSLib from “not implemented exception” to PackageKit. I hope we can find a way soon to make PK work on Ubuntu as well.