The Twin I Beam setup doesn't work all that well either! Ever seen one backing up? the wheels lean in on top like they are gonna fall over. If you back up and hit the brakes hard they'll hardly get going ahead again. If the shocks get a bit weak they will "jack" the front end one way or the other on big bumps, sometimes 2 feet before you catch it. I much prefer the older trucks with a single I beam under them.
Sidney Allard used the same setup in the '50's on his race cars, and he put the inboard pivots as low as possible. That way all the camber change is the same way, in more on top, and more predictable. Still didn't work though, even with a monster sway bar forcing the wheels to move more or less together. Just not a good setup for handling.