Are you confusing the crosswalk with the shoulder? No one should be making a right hand turn from the left lane. In the situation shown in the OP, where both the car and I are in the left turn lane, I'd pull up to the stop line, just to the right of the car, up by their bumper where they can easily see me. I also use hand signals all the time, though I'd put my arm down before or when the light turns green; I'm just trying to signal my turn, not block the car next to me.

Frankly, though, if the car gets rear-ended, you might still be in harm's way even if you're next to the car, but your chances are probably better than if you were between two cars.