A source of viton rings from the Czech Republic.

[chrismb]

This ebay seller might be of interest. I am just sorting out a big order (well, 'big' on my small scale!!) for them right now;

http://stores.ebay.co.uk/BOHEMIA-SEAL

They advertise such a range of seal sizes that I presume they make them to order...

[Doug Coulter]

The main problem is that McMaster doesn't ship directly to your country. We can set up thing like that through this board, though.

http://www.mcmaster.com/#o-rings/=a4bcaa

Every imaginable size is made, and isn't too expensive either.