Chrome finish buttons:
http://cgi.ebay.co.uk/NEW-BUTTONS-ki...item51845a3430

Antique finish buttons (they look great and would match your cantle well):
http://cgi.ebay.co.uk/NEW-BUTTONS-ki...item51845a23da

Interesting St. Andrew's chrome buttons:
http://cgi.ebay.co.uk/24-St-Andrews-...item1e58f65643

Celtic design chrome buttons:
http://cgi.ebay.co.uk/2-Highland-Kil...item1e58a767da

Stag horn buttons (work well on tweed):
http://cgi.ebay.co.uk/NEW-BUTTONS-re...item29fcb4043d