Square's Western studios kinda make sense to be sold. But, the rumours said it would be "crazy acquisition" and I don't think it would be that crazy. When thinking about stuff out there:
Konami - Kinda "dead", so you're picking the IP and rebuild from scratch. I think it would be big because of the heritage, but difficult to get stuff moving with them. Were rumours earlier in the year.
Sega - Have some solid PC and console studios that are actively making good stuff, plus of course the back catalogue. Would be big, and their were rumours at the same time as Konami.
Square Enix (whole thing) - I just can't see it... which I guess means it would be crazy.
Capcom - Similar to SE, I just can't see it...
Bandai Namco - Don't think anyone would care (lol)
Atlus - Would be a big deal amongst the hardcore
Koei Tecmo - Again, don't think anyone would care
ActiBlizz - Would be huge, probably too much $$. Not worth buying imo (Blizzard is on a downward spiral; acti is nothing but CoD)
Take2 - Would be huge, probably too much $$.
EA - Would be huge, probably too much $$. Plus a lot of the value is the licensed sports games that "need" to be on other platforms for their contracts AFAIK.
Ubisoft - Would be huge, probably too much $$. But, they just make the same game again and again, so have 'em.
Smaller stuff: WB Games, Paradox, Devolver - some good pubs, but would not be "huge" imo.