[Eliot Ness]

If you have a good hardware store locally I'd try there first.... often they have a good assortment of things like that.  Next place to look would be on-line like the link above to Radio Daze or even scouring eBay for some.  I've found McMaster-Carr to have a great assortment of stuff like that:

http://www.mcmaster.com/#rubber-feet/=v6dj3p

http://www.ebay.com/sch/i.html?_from=R40...t&_sacat=0