Yes, you can do the same type of panning in Cubase, but it seems to be only in Cubase Pro. If you go to the mix window and hover over the stereo panner, a tooltip may tell you “Balance Panner”, but you will also get white disks appearing on the left and right ends of the panner. The right disk has a down-pointing triangle, indicating a drop down menu. From here you can select “Stereo Combined Panner”, which is just like the ProTools feature you described. The left disk turns the panner off, but that will just make the channels go hard left and hard right.
If you don’t have the Pro version, you can try Voxengo’s MSED (which I remember getting free without having to buy anything). I love it. Among other things, you can turn down the S channel to get mono.