Just throwing this out there, but for anyone with a left hand orientation problem, maybe the problem isn't actually in the left hand (or wrist, or elbow, or shoulder).  When I finally picked up my violin to learn how to play it, I was very concerned that I was doing something wrong when I realized I couldn't arch my fingers enough to play on the G without their interfering with other strings.  Half of the time, I also had the neck at the bottom of the valley between the thumb and index finger.  I think being a beginner was what clued me in to my problem: the violin wasn't oriented properly.  Because I was still getting used to the instrument, I changed the way I held it and the orientation of my shoulder rest until I found a comfortable playing position, which also solved my left hand problem without my realizing it.  Maybe you could experiment with different chin and shoulder rests that would support the violin at different angles to see if the same thing happens for you.

EDIT: I meant to mention this site: violinistinbalance.nl.  It's kind of tough to click through, but it outlines a study that was done over a year or two at what I assume was some kind of music school.  Basically, they found that when a violin's setup was properly fitted to the player, pretty much all of the mechanical problems solved themselves.