Eh... The best supporting cast? If he really wanted to be could go to Golden State. With the cap raises there are going to be a lot of teams that could squeeze him under their cap. Also there's zero guarantee that Russ won't leave the very next year.
Also, you can't just easily scheme around your center being the worst defensive big in basketball. It's possible if you have super elite perimeter defenders (although Ibaka helps a lot).
I'm talking of teams with the cap for him.
It will most likely only be OKC or Was.
GS already has alot of huge salaries on the books as is.
Green at a near max, Klay, Steph eventually on a max, and Bogut, Lee, Iggy all make 10+ mil.
Barnes is due a new deal after next year as well.
I was talking realistically when teams like Mia, Brooklyn, LAL, Knicks, etc are mentioned.
If Chi could scheme around Boozer, OKC could around Kanter, and already had this convo. Again, if they leave, it's because they dont want to be in OKC, not because of what other teams have on it's team.
No one else has the supporting cast OKC does when they're healthy.