Mafell has a new model plunge saw that has such a system, (the pointer for the depth guage can be set so it either shows the cutting depth with or without the guide rail).
Mafell was the company that used the springloaded riving knife first on their plungecut saw, and festool later incorporated this feature in their TS55, along with other new features of their own like the fastfix blade change and the anti-splinter guard.
With all the other brands bringing saws with different features (makita with the anti-tilt thing; dewalt with the anti-kickback, depthscale in inches for the US-market, alternative plunge mechanism,...; mafell with the unique blade-change thing, the mentioned depth guage, cool sidecover with marking tabs for the "reach" of the blade,... it will be interesting to see what festool will come up with when they will introduce new versions of their TS saws.
(Not that I personally think the TS saws really need improvement; and all the saws mentioned above are compatible with the festool rail system so it's also an incentive for festool to make more accessories for their guiderails that improve "the system".
As for the depth setting, for me it depends on how the workpiece is supported (I don't have a dedicated cutting table for ripping ply, usually whatever's at hand on saw horses, or on the stack) Usually about 1 to 1.5 cm more than the workpiece, exept when I use the mft I got recently. When you use dustcollection I don't think it's necessary that the gullets go all the way through.