I think the Dublin bootleg from the official tapes must be taken as an encouraging sign.
Dixie ChiX and Shania are two acts who put out DVD's before thier tour ended. I think U2 put out their DVD a couple weeks before the elevation tour ended in 2001.
Bowie seem to go out of his way that the Dublin shows were intended for release. All his other video projects over the past decade were all stuff he just filmed for the archive.
Lastly, there's been no live TV appearances this tour(except for a couple things in sept and oct) with none scheduled. Is Bowie clearing the decks for a live DVD?