Several Nvidia partners have confirmed that they had to decide to cancel GTX 285 and GTX 275 based products, as availability was simply disastrous.

We still don’t now if this is Nvidia's strategy to keep the market hungry for Fermi or they simply didn't order enough wafers, but availability of GTX260, GTX275 and GTX285 was so bad that many decided to drop these products and wait for Fermi.

http://www.fudzilla.com/content/view/15919/34/