It's confusing enough to have two upcoming Professor Laytongames -- Unwound Future on DS and Mask of Miracle on 3DS. But there's actually a third Professor Layton title on the way! In the UK, on October 4, Manga Entertainment is releasing the Professor Layton and the Eternal Diva movie on DVD and Blu-Ray.
The film will be released in disc-only DVD and Blu-Ray editions, as well as a DVD collector's edition. If you really want to drop some money on the Layton movie, the DVD + Blu-Ray Combi Pack includes both the DVD and Blu-Ray discs, as well as the gorgeous collector's edition packaging and a book of storyboards.
If you're in the US, ordering from Amazon UK is as simple as signing in with your American account. That leaves only the issue of region-coding -- at the moment, there's no information about the coding on either version of the movie.