as maxx said,both pairs of pistons had to be contacting the braking surface(at the same time),before any!!! braking force is gonna be there.
in a system wich lives from hydraulic pressure,think that over.where would that rising pressure come from,when either maggie OR disc pads touch ground?
you´d have a brake that shifts the first pair of pistons out,they touch the braking surface,then the hydr.pressure would first shift the second pair out,THEN brake force would be applied on both pairs with rising hand force.
nope,doesnt work with a normal brake lever,but:
check this out:
http://go.mtb-news.de/redir/clickGate.php?u=RN1hJwP9&m=1&p=2YPGEU221K&t=z245JY2e&st=&s=&splash=2&url=http%3A%2F%2Fwww.pinkbike.com%2Fnews%2FReality-Redesigned-The-GAUNTLET-Ep1-HM-12.html&r=http%3A%2F%2Fwww.mtb-news.de%2Fforum%2Fshowthread.php%3Ft%3D519145%26page%3D7