Repped man. I'm about to hit that tonight. It actually feels good to bend it that way to stretch it out. Just going back and up kills me.
What do you guys got for traps? My main trap isolating lift is shrugs. 5 reps, hold up 5 seconds, 4 reps hold up 4 seconds.... You get it.
I too get joint discomfort due to arm position while squatting, specifically in my ulnar nerve. So I try to mix it up as much as possible when I do legs. I feel most comfortable doing deadlifts and lunges as the core movements.
Personally, I don't isolate upper traps. I feel like they get hit plenty during deadlifts. But any type of shoulder elevation (like shrugs) should target your upper traps. There's a lot of variations:
http://www.exrx.net/Lists/ExList/BackWt.html#UpperTrap