There are zero chances of anything other than a lot of time with an electron microscope to extract private keys from the device. IIRC.
I don't know about the electron microscope specifically, but surely one can do it with suitable scientific equipment. Not with something that you but at Radio Shack, though.
Surely the suitable scientific equipment you are referring to, is the Electron Microscope, and nothing less.
I suppose you are right, for the readout. I was thinking of the first step, exposing the chip.