Maple Story 3D and Maple Story 2. Does not seem like a hoax.

Kava Tina story is more than likely its own game. Its just the same people that made MapleStory is making this game (There will likely be cameos from Maple in this game )

But, KavaTina Story is supposed to be showcased at GStar 2008. According to mmosite, Nexon is showing 3 secret projects there. MapleStory 3D, Project Neo, And Project Star. Project Neo has already been confirmed as the Kart Rider sequel, and Project Star seems like its going to be an MMOSG like Second Life. Kava Tina Story looks like a regular MMORPG (from what I saw in the tiny teaser). -shrug- But I could be wrong because the same site says that Mabinogi:Heroes will also be unveiled. And that couldn't be either of those two.