Agree trixiebabe it is a shame. I am going through every custom build pc site to see if they have it and how much my spec would cost. PCS prices seem very competitive but I really want the Cosmos S. The Corsair case seems nice though.
If you really do want the case that much stop being lazy and do what Sleinous said! it's really not that hard and it will definitely be worth it. Just check and make sure the size isn't greater than 600mm x 300mm x 630mm (Height x Width x Diameter).
We used to offer the Cosmos S, but it's been around for a while now and lost its initial popularity. I assume based on your saved quotes you're wanting to order it on our overclocked configurator: http://www.pcspecialist.co.uk/computers/intel-1366-overclocked/
Large cases are "overpriced" because we spend an extra £20 on specially designed packaging to cater for the weight during delivery. We'll remove the Cosmos S again then.