Square Enix looks poised to offer Dissidia: Final Fantasy as both downloadable game and UMD title at launch on 18th December.
If the listing on the Sony Japan website proves accurate (well spotted, Siliconera), then we should be able to grab the title directly from the Japanese PSP Store. This involves pretending to live there, remember.
And, what with Square Enix still fathoming out European launch plans, that would seem quite appealing. The arena combat spin-off will be in Japanese, of course, but with the emphasis on fighting that shouldn't matter too much.
This sort of behaviour was started by Sony during the Tokyo Game Show, after the platform holder promised all first-party PSP games would simultaneously appear on UMD and the PSP Store.
There are some videos of Dissidia: Final Fantasy to watch over on Eurogamer TV.