Michigan/Ohio/Kentucky/Tennessee cases were grouped and are at the 4th circuit court. The hearings were done in August, decision expected in October or November.
Actually, that would be the Sixth Circuit. 
But yes, you're absolutely right. All four of those states are locked together. If it rules for marriage equality, it will be legal in all four of those states. If it upholds the bans, you can surely expect the Supreme Court to take it up. I'm starting to really wonder if SCOTUS will ever make a definitive ruling on the issue. Any circuit court that upholds a gay marriage ban at this point could very easily face summary reversal.
It's no longer beyond the realm of possibility that every circuit court might rule in favor of gay marriage, thereby preventing the Supreme Court from ever having to hear the issue. If I were Kennedy, I'd be kind of bummed if I never got to write that big decision that I'd clearly been building up to all these years.
Well, that's part of why the Court hasn't taken the cases IMO; Kennedy wants
Windsor to be that decision because he doesn't want it to be assigned to one of the other justices.
