Jon, I'm with you. I've searched through Machine Pins, Clevis Pins, Cotter Pins, Spring Pins, Spirol Pins, Roll Pins, Dowel Pins, Taper Pins, Alignment Pins, Self-Clinching Pins, Grooved Pins, Straight Pins.
I found this under 'knurled pins'. Are we getting closer?

If we can't find the actual piece, I wonder if this is something can can be (*ahem, psberetta) machined? 