Accessible Cabinet Top

While reading "adjustable cupboards," I was reminded of another idea I had a long time ago, but never told anyone. Most kitchens have a space above the cabinetry that either collects dust or those rarely-used cooking items or both. I propose putting another set of cabinets there, or perhaps just a shelf, that slides forward and lowers to an accessible heighth. The tricky part will be designing an inexpensive mechanism that will track horizontally for a fixed distance, and then vertically or a vertical arc in a controlled fashion. I picture a set of easy-guide drawer slider rails mounted to some type of four-bar mechanism that slides the shelf / cabinet forward to the front edge and then lowers in an arc. Adjustable springs or damping would be needed to respond to the variable load.