Squeeking sound when turning left, and only left... what could it be?
 

Dealer couldn't figure it out for some reason

Squeaking when you turn the steering wheel or a cyclic squeaking that ...
 

would be related to a component that is rotating with the front drivetrain (cv joint boot, etc)?

My guess is the steering column ... search for posts re: creaking (not squeaking).
 

Mine used to creak while making (I think) right turns only (and only when it was above a certain temperature outside). I had mine fixed under warranty, but I'm not sure what was done. I believe some people have fixed it by lubricating something under the dashboard with white lithium grease.

Maybe you ran over a pig... nice one. :-)