I've purchased from aquacon.com liked the product. Had it for about a month and half now and the growth on the rock is starting to pick up. Have also heard some people ordered from this site that were happy.
Oh yeah the link that cadbury gave you also has some cool rock. I live by there and on Saturday's am able to go in (only day they open). Alot of there rock has some really cool growth on it. Just not sure how cured it is, but it has alot of cool growth.
You might try gulf-view. I got my last batch of rock from them and was very impressed with the their premium rock. Lots of live growth and color to it. <a href="http://www.gulf-view.com" target="_blank">http://www.gulf-view.com</a>