rcb equipment might have them?? I bought 2 x 18L kegs off them for US$12 each and had them shipped to oz by USPS (took around 2 months) for US$21.20. At 0.75 exchange rate that works out to AUD30 a keg. Its worth it even in small quantities.
Try
http://www.rcbequip.com/index.html
With the idea...