The problem with walking away is so much for stellar credit.
But if you do consider it, consider this.
Use your stellar credit to buy another place. Close that loan, move into new place, walk from old place. They can't kick you out of your new place as long as you live up to the terms of mortgage. Your credit rating will take a hit, but you'll alteady be in your new place and won't need credit for the next few years anyway.