The LF444CN Quad JFET Input Op Amp is used in several MFOS projects which require both their ultra high input impedance and their ultra low offset currents. These are 14 pin DIP through-hole parts.

Sorry about the price on these but I have very limited stock and they're getting harder for me to find in DIP form. I believe Jameco sells them for less.

See the LF444CN Quad JFET Input Op Amp data sheet for complete specs.