I'm not sure how it works on the 3DS, but Vita has been built around having a great online infrastructure. I can't imagine a Monster Hunter on Vita will stick to local multiplayer only. At least as far as Vita is concerned, I think the days of games having local multiplayer only are long gone.
Speaking of, Sony's holding a pre-TGS press conference on the 14th, a day after Nintendo. It'll be livestreamed and liveblogged -- http://www.siliconera.com/2011/09/08/sony-to-hold-pre-tgs-press-conference-as-well/
Also, Persona Ultimate trailer --
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peace comes from within