I may be way out in left field, but couldn't you constrain the top of the piston to the top of the sleeve, and the bottom of the piston to the bottom of the sleeve? And then also anchor the top of the sleeve to the chassis, and the bottom of the piston to the wheel? If it retains the shortest distances between each point, then they should always be in line. I wouldn't try to link them to the constraints that are actually controlling the suspension... since this is a visual issue only, they need just enough constraint to keep them in line.
My 5th post... I might be crazy.