Thanks for the input, this is just what I needed to keep me going.

Wow, what a great start! What is polymer clay? Do you fire it to cure it or does it cure or dry?
I'm currently using a product called Super Sculpey. I actually tried two different techniques. For the first pin, I carved the initial design out of un-baked clay. Notice that the edges on that piece are a little rounder. For the second pin, the design I like the most, I baked the initial rectangle piece before I carved out the design. Both methods have their advantages/disadvantages.

What metal are you gonna cast them from ?
I plan to cast these in pewter, since it is fairly easy to work with and has such a low melting point.

Oh neat!!! Great idea. This is (or seems to be) doable with common household stuff, and maybe a blow torch?
I initially though I might use the blowtorch technique but a small melting pot is not that expensive. Since I'm doing this in my garage, I mean workshop, I'd rather not risk the fire hazard.