I think these would work the same way on the upper cabinets.
http://www.ikea.com/us/en/catalog/products/20049538/

Well, you could buy the legs separately and install them. The legs are sort of two pieces. There is a "plate" that screws into the bottom of the cabinet, and then the leg slides into that. The toe-kick then clips onto the legs. Or you could just build a base/plinth out of lumber and rest the cabinets on that.

You just have to saw off the tab from the leg connecting piece, since the shallow cabinets don't have the little indentation on the bottom. Ikea does sell what they call shallow base cabinets, which are just the wall cabinet + a set of legs. If you go to ikeahacker.com or ikeafans.com you can see many examples of how people have done this. Some have also used the mounting rail instead of legs for a floating effect.