Sounds like a fun item!
Since Renekton's W autoattacks twice, can I assume that it will proc Tiamat twice?
Also, something I've been wondering for a while, do you have any plans for AD-centric items with mana? Manamune is nice and all, but it'd be nice if I could pick up something on a jungle Kha'zix for a bit of mana and not feel like a fool for spending money on more mana than I'll ever need.
I believe there was mention of a jungle ad caster item that had mana regen.