There is
http://www.tanzmaus.de/ , go to "Zubehör" and then "Straß & Kristallsteine" - they sell Swarovskis per piece.
For larger amounts:
http://www.strass.com and then go to "sew-on Stones" , they sell per units which can be different amounts depending on which type. Many different colors, shapes and sizes, yummy!