7 card stud hand...

[ChipFish]

He was pot comitted, and simply was hoping his queens were good, when he re-raised you....
Each card on each street you say was an x.
Well, If it's only an x (under queen) than why wouldn't he stay?
He's making a stand is all. (Probably a bit early to make a stand but that was what he was doing).
I really don't think he was looking for that 3rd queen on the river (Although he wasn't complaining).

I also think you put alot more of your stack in then a pair of kings could justify.
This is 7-card stud.... you have to worry about flush, straight but if neither of those are visible, could you beat 2 pair? That is entirely possible, and definitely not unlikely.