[dcb]

re: pushrod suspension, you are adding sprung weight though, in the form of a pushrod and a bellcrank. AFAIKT it does allow a progressive "spring rate" without progressive springs (as do other non-pushrod/rocker geometries), but still it is extra weight between the spring and the road and thus "sprung weight", just like a pushrod engine needs the pushrods and rockers to be moved by the valve springs half the time.

Unless spring tension increases non-linearly (and dramatically) with weight, I don't see the "reduce unsprung" weight argument as valid, not yet anyway.