Circular flat pressure sensor to measure force and stretch?

Hi,

I am looking for assistance in finding a suitable sensor or sensor combination for an application I had in mind. I am developing a musical instrument controller, and I need a fairly large, circular flat sensor (diameter of 23 cm or so) that will act as a stretched membrane (like a drum head). It should be able to detect pressure at any point on the surface, but it should also be able to detect the amount of stretch if it is depressed (while continuing to detect pressure on the surface). Is there a sensor design available for this?

Thanks for any assistance that can be offered.