Lisa I found some more information on making your own support and a few links to articles about technique.
I found this description to make your own silverpoint support:
Coat smooth, stretched, acid-free watercolor or drawing paper with white gouache.
The gouache can be tinted. Thin gouache to the consistency of cream and apply with wide flat brush using parallel strokes. Wait till dry to draw.
Other coatings for texture support are bone dust, gypsum and chalk, mixed with a glue size.
This is a neat article by a Wetcanvas Member
"Silverpoint Drawing Methods"
Author: Marilyn_Schlueter, Contributing Editor
This article says to buy your wire on ebay, of course I should have thought of that.
Another article site
Another Thread at WC for some ideas:
Playing with Silverpoint
Instruction from Daniel Smith website
Silverpoint on Prepared Board
by Diana Fairbanks