It looks like the WiFi Sync app by Greg Hughes, which had previously been submitted to the App Store, has made it's way to Cydia. The app connects over a wifi network to a computer running the client app, and syncs your phone as if it were connected via USB, and is available on the BigBoss repo for $9.99.
While not officially supported, it does work on the iPad. :)
Currently the client app is mac only, but a version of the software compatible with Windows will be available shortly.