I'll add this comment on the comparison: Any rear roll center height with a live axle is primarily determined by the height of the parts that provide the lateral locating function of the axle. It can be changed somewhat by link angles in a triangulated 4 link but the fact that the angled links are ABOVE the axle automatically moves the rear roll center well up in height. It can be lowered by chagning the links' verticalangles but you can only do so much with that. And, if you reduce the relative angle between the upper links you can lower the roll center more....but if you reduce the relative angles a lot to try to further lower the rear roll center, you lose the locating function and the rear starts moving around a lot sideways under the car. (And, think about it: as your reduce the upper links' relative angle to zero, then you have made a 4 parallel link design anyway!)
The use of a panhard rod instead for the lateral locating fucntion allows to move the rear roll center down a LOT; you can even get it below the centerline of the rear axle. You can add rod end mounting holes and move the rod (and roll center) up and down for tuning. Or use a jackscrew at the chassis end mount if you really want to get wild, like NASCAR. The one fabrication issue to get the rear roll center down low is to make the chassis end mount long and stick down a lot; that takes some fabrication but that has been solved many, many times for racing and production cars. (For a good production example, look under an Opel Manta A or B or the Ascona A or B. (And the Kadett C's also, if I recall right.))
NASCAR has gone this way years ago for this reason. And most or all of the successful RWD, live axle rally cars in the 80's used the 4 parallel link and panhard rod. It does as said with the rear roll center and is rugged. So all that should clue everybody into this concept... for street and track handling. (Roll centers usually become a very secondary thing if drag racing; they can be high or low and not have much or any effect on straight line weight transfer, etc.)
BTW, my racing experience is 95+% in rally, if that tells you anything. Rough surface handling is the holy grail there.