Challenges would be:
1. Product liability. Someone's going to screw up install or fab, losing steering control at 70 or on the side of a mountain.
2. Getting around shock damage, which often occurs if the shock doesn't at least have spherical bushings. Often even if it does. With replaceable trailing arm tubes, alla Alternative Impact in the 90's and early 00's, the tube needed to collapse before the shock rod bent. Needed spherical control arms, too. But the implications of failed design, manufacture, or install on a trailing arm isn't as dire as an a-arm. Was much less complicated, too. If anybody has thought seriously about this, it would be Dan.