This is probably old hat as they say but stuck in lockdown I went back to some old stuff and wondering if the Z bar spring system used in the 1960's by Porsche among others still had any potential if complemented by an anti-pitch fifth spring?
The Z bar is an alternative to coils and it is Z shaped anti roll style bar which provides only single and double bump stiffness. It's used with a conventional anti roll bar which provides all the roll stiffness ( and some single bump stiffness).
If you link the mid-points of the front and rear anti roll bars with another Z bar this provides full pitch control but nothing else - except a small degree of warp control as the movement of a front left bump and a right rear bump on the centre points of each anti roll bar will trigger a reaction to warp.
Of course it may , or may not, be desirable to largely isolate bump and roll resistance at each end?
Also the clever bit would be to arrange the damping forces in a similar manner - maybe by adding a damper near each end of the Z shaped anti pitch link bar to control pitch?
