Okay this is a bit early, but still...
I'm interested in making my own pickups, too and I need some info on the materials. The commonly used copper wire for the coils seems to be AWG#42, right? What types of magnets are used in pickups. I read about Alnico, Alnico II and Alnico 500...I've found a supplier here in Germany who sends Alnico 500 rods, 6mm diameter, 25 mm length, which would be the ideal measurements for a pickup I think, but do I want Alnico 500? I know John Fishers site and his idea of making the bobbin out of a wood core and a plastic CD tray is genius, now all I need is the wire and the magnets and even more patience :-)
so long
ace
P.S.: I know what AlNiCo stands for, what really interests me is the tonal differences between the different types