User blog comment:Ado edem/Next ultimate skin?/@comment-5514182-20130608153823

They said that they've been working on it for a while, so Zac, Vi, and Kha'zix are probably out.

Voli, Xin, Nid, Blitz, and Olaf also have gotten skins recently, so thye probably aren't working on another skin for them either.

This leaves Mundo, Eve, Lee, Leona, Morde, Rammus, Rumble, Talon, and Udyr.

I'm betting on Talon, just because he's so underrated.