[Update: For what it's worth, user BRS547 Ignis has opened an internet petition for Sega to localize the game. Sign it!]
There's no getting around it: The PS Vita is aching for games right now. Sony's press conference almost seemed to bury the suffering handheld (even boss-man Shuhei Yoshida regretted that judgment call), but thankfully for the fretful, the Vita had a strong presence on the show floor itself, right in the path of the games press. And the admirable few not too dazzled by the show's marquee titles had a chance to explore Sony's Vita-blessed booth...and spotted a number of quirky, unique releases, among them Hatsune Miku: Project Diva F.
Now, a pessimist could easily dismiss this presence as a sign of desperation on Sony's part, stuffing the booth with warm bodies cartridges to make up for the dearth of western-appealing titles. In heartening news, however, the game was localized. Menus made it easier for the Nihongo-impaired to check the game out, and grok its universally-understandable rhythm-game mechanics. Better still, when asked Sega First-Party Coordinator Andrew Wong noted a "good" level on interest in the game at the show.
Of course, one should take a grain of salt with this. Similarly hopeful comments have been made before by western Sega personnel *coughValkyria3cough*, and Sega Japan calls the shots in the end. And given its precarious financial position, it may not be inclined to take even the relatively minor risk of localizing a niche game.