GungHo might be a surprisingly strong contender. They have the money and the interest...
Edit: You know, the more I think about it GungHo might actually be the ideal candidate.
Why is that? Well, first of all there's the basic issues like the fact that they can probably afford it. In case you don't know, GungHo has been doing really well lately, in no small part thanks to a mobile game called Puzzle and Dragons. Maybe you've never heard of Puzzle and Dragons because its popularity is mainly in Asia, but it's actually the number one grossing mobile game in the world, on both iOS and Android. Eat your heart out, Angry Birds.
Now you might think that a company with a mobile game that successful would be all about mobile games, but that really doesn't seem to be the case with GungHo. They have their fingers in a lot of different pies, and in super-success in the mobile space doesn't seem to have changed that. They recently acquired Grasshopper and have largely left them to do their own thing, so that's a good sign. Heck, do you know those PS1 Imports, the random obscure untranslated PS1 Classics put on the US store? GungHo was the main company behind that. Now while it's quite probable that the PS1 Import thing has been profitable simply because the expenses involved are pretty low, we're probably talking about a miniscule amount of revenue. Most big companies simply wouldn't bother with it, profitable or not. But GungHo doesn't shy away from random, obscure things.
And they're clearly ambitious and want to expand. I remember there being news a while back about the comments their CEO made with regards to wanting to surpass Nintendo. So maybe they lack humility, but they clearly want to be a player everywhere. One place their are lacking is in western localization (their success has largely been in Asia so far), which is why you've seen them team up with Xseed for a lot of their recent releases (Ragnorak Odyssey, the upcoming Killer is Dead). But Atlus USA might make a pretty good fit there too. They've localized lots of non-Atlus stuff in the past (though I feel they've been shying away from that lately...) so they ought to be able to handle some of GungHo's stuff too. It seems like a good fit.
That's why GungHo might want Atlus. As far as Atlus goes, GungHo offers financial stability without intruding on their creative process. So yeah, GungHo-Atlus 2013!