Thanks for the input everyone. Although I like the idea of doing things myself I can see this easily turning into the most expensive kilt pin ever sort of thing. I have enough hobbies and not a lot of free time, unfortunately.

Tattoobradley - I like the erlenmeyer flask pin. In fact it's not too far off from one design I was thinking of; the "unofficial" symbol for geochemistry is a test tube crossed with a rock hammer.

Tartan Hiker - ceramics might work for some people but I am always smacking my kilts pins into things and I'd hate to break one. That may be a good lead for other though.

Riverkilt - I might be interested depending on what they charge. I can PM you if you need more info. Thanks!