A search for “sterling
A search for “sterling silver wire” turns up all kinds of options, including Riogrande and Amazon.
The only issue with using silver is the reaction that can occur with certain colors of glass, and the fact that it will stain your shelf and can potentially cause problems in subsequent firings, until the silver fuming fires out.
You might be interested in a blog post I did, after we had a Bullseye rep come to our glass guild meeting and talk about reactions with glass and metals:
Jester’s Baubles Fused Glass Designs