They're surely trying to get Kojima.
It'd be FFXIII on 360 levels of crazy if it happens.
Well, let's look at who could realistically house such a titan of the industry:
Nintendo: well, they could definitely afford it, but I don't think Kojima's games really gel with anything Nintendo does. From his point of view I don't really see this as a good deal as he always seems to strive for cutting-edge tech and visuals, which isn't Nintendo's domain at all. They could however be a wildcard and try to appeal more to a different gamer, like they have done with Bayonetta 2 or Devil's Third. Anything Kojima makes would likely be a much bigger and more expensive production than either of those, however.
Sony: perhaps the most logical assumption, largely because of his history with them and their platforms for almost a decade, as well as Sony's investment in Japanese development at the moment. They already make the kind of games which gel with Kojima's development style, and both parties have prospered from the other, so one would assume there's a good relationship there. I think the biggest issue would be where would Kojima fit into the organisation? SCE have made quite a few cuts in the last few years and Japan Studio is just coming out of a very dark time, so I doubt they'll want to add a significant number of new staff who would likely be piggybacking with Kojima.
Microsoft: this doesn't strike me as likely, mainly because MS don't really seem to care about Japanese development any more (with the exception of Scalebound), although if anyone could convince them to set up a dev team in Japan it's Kojima. I think they're so laser-focused on keeping up in Western markets that they're not going to invest in new major Japanese projects.
Square Enix: I seriously doubt it. Their type of games don't really gel with anything Kojima makes and I think they're too busy trying to sort out their Japanese development arm to add another major team which wants $40 million to develop a new game.
Bandai Namco: again, I can't see them being able to accommodate someone like Kojima with his epic budgets, and his work isn't really like anything else Bamco produce at the moment. Of course, it could be that they want to invest in a new field and make an expensive lavish story-driven action adventure, so who better to get on board for this than Kojima?
Capcom: I think they're back in profit now after a few rocky years, aren't they? In which case I think they're probably the most likely Japanese publisher to hire him. They already make plenty of action adventures so it's a genre they have lots of experience in, and they make a lot of games of similar scale and budget to your typical Kojima game.
Platinum: I guess out of all the Japanese independent developers Platinum would be the most likely who could house Kojima, partly because of their history with him thanks to MGR: Revengeance. On the other hand I don't see him going to a work-for-hire company like Platinum, and instead he's going to ideally want creative control with a large budget.
Set up his own small indie studio: I think if he wants to maintain full creative control and own his next development this is his best option, but he'd then need to start working with a budget probably 1/20 of that he's used to. He might go the Kickstarter route like Inafune, I guess.
Set up a mid-sized studio and partner with a Western developer: I'm thinking similarly to Mikami and Tango Gameworks, and I think this is one of his most likely options. I don't know who might be interested in partnering - maybe Bethesda or EA? Ubisoft perhaps? Deep Silver? Doubtful on Activision, Warner or Take Two.
or SFV would remain exclusive.
