They'll tell eventually... I'm rather surprised about this one, it's the first eeveelution that is going solo in it's generation. Then again, I'm surprised they have a 6th already anyway, it wasn't long ago they had 5!
In all likelihood, if they come out with another eeveelution, they'll do two, and they'll likely be opposites. Remember that this originates in Japan and 9 is something of a lucky number there, true, if we count Eevee then one addition and we'd get nine but if we don't then we'd need two.
Also remember that every time they've added another pair (since the first three eeveelutions) they've been something of opposites, first was "night" and "day" (umbreon and Espeon) and then was "cold" and "warm" (glaceon and leafeon).
Personally I'd like a ground type, that way all of the eeveelutions would have at least one other eeveelution that they were strong against and at least one other eeveelution that they were weak against, as it is jolteons have nothing to fear. But if that were the case then they'd likely need to add a ninth as a flying type, which would be kind of odd but kind of cool if you think about it...
Ah, how silly of me, I originally thought you'd used the BG from Megaman 3, it took me a bit to realize it was from Megaman 2, that's my favorite Megaman game! I should have recognized it! Grrrrr!
I would've figured if there were two Eeveelutions to introduce that they'd both be mentioned for the "Eevee-Friends" movie rather than just one. You know, after last year their Pokemon Centers had a whole Eevee merchandise extravaganza.
I'm guessing this newer one "Ninfia" is a Normal-type evolution, possibly with many moves being healing effects.
I'm still guessing there's another Eeveelution that hasn't been announced yet. I'm just going by the pattern we've seen in previous generations. Gen 2 brought Umbreon and Espeon, Gen 4 brought Leafeon and Glaceon, and now Ninfia has been mentioned for Gen 6, but I bet there's gonna be another one.
I'm just going by wild mass guessing here but since Ninfia looks quite feminine, I figure the other Eeveelution for this one will look hardy and masculine, as a sort of reference to X/Y chromosomes.
If my guess is right, I vouch for the as-of-yet-unannounced Eeveelution taking the place of Protoman. XD
I saw a better look at it. I wonder what the English name will be and what type it is. I would guess Flying because of the Butterflies. The next question is who will be the new Pikachu Cousin for the 6th Generation.