My friend Judith came out to work on Tris yesterday. I was glad to have her experienced eye on him - she's known him as long as I've had him, and she has an outstanding perspective and knowledge of equine body mechanics.
We walked him out a bit for her, and he's quite ouchy at the walk and to her eye, compensating with a swing of his left hind. She also detected heat in the heels, coronet band, and a bit up into back of the pastern of that foot, and noticed something which I had seen in the past few days: the sulcus of his frog (the grooves beside and on top of the frog) has gotten incredibly deep.
He turned out to be tight in his left shoulder, though she approved of the work I've been doing on his right shoulder to loosen him up there, and a bit in his lower back.
Game plan: bute him until the farrier gets out to do his new shoes, in about 2-3 weeks. I checked in with the vet today and she agreed, and if 2 weeks or so after he gets his foot re-balanced he's still just as off, we'll start with another round of x-rays.
I also picked up some basic thrush stuff (Absorbine Hooflex) at Tractor Supply and I'll be paying extra attention to his feet and dosing him from time to time with that just to make sure he doesn't start an infection there, too.