The preceding pictures illustrate the point I tried to convey earlier. There is no inherent weight reduction in adding the linkage and bellcranks, etc... But it is the reduction of the unsprung weight RATIO which is important.
An example using the pics above and assuming a few things like:
weight of unsprung suspension components - 400# (100# x 4 corners)
weight of vehicle - 2400# (sprung + unsprung)
One arrives at a ratio of 400:2000, or numerically .20. My contention is the weight is not removed from the vehicle but simply transferred from one side of the ratio to the other. Isolating the heavy components from the vertical travel of the suspension (ie, outboard of the pivots) will have a profound effect on that ratio. If you bring suspension elements inboard of the pivots properly, their CG will undergo minimal displacement through the range of suspension travel. The dampers are virtually completely removed from the unsprung weight (depending on geometry, their center of mass may slightly move vertically during suspension travel as shown in the design pictured above).
Let's say that of the 100# at each corner, 25# was the spring and shock combination. The new ratio would look like:
4 x 75# = 300# unsprung weight
2100# spring weight
ratio = 300:2100 or .143
This yields ~28% improvement in the ratio.
Let's say that you also now need another 20# at each corner split evenly between sprung and unsprung to acheive the inboard suspension. The numbers become:
340# unsprung
2140# sprung
340:2140 gives a numeric value of roughly .16, which is still ~20% better than where we started (.20), but will cost us 80# to acheive. The trade off is where to balance the weight gain and complexity for feel and performance.
Granted, I did choose the numbers to make the math easy but also with some eye toward reality... Figure 30# for a wheel and tire, another 30# for a rotor and caliper, 40 for the remainder of the components.
The end result is that reducing the weight or presence of components moving grossly with the suspension will have a pronounced effect on the unsprung to sprung weight ratio of a car. With more stuff grounded to the chassis at both ends the car will be more inclined to handle better.
I hope this makes sense as it's been ages since I thought about anything of this subject and I may be a bit rusty, but I enjoy the mental exercise though.
Chris