I don't believe we are releasing the ships separately, though that particular decision is completely out of my control and hands, I do the xml work not the ship modding
Our ship modeler is still working on some texture work on the established designs (which can be seen above) but he does have other ships planned.
As for the Excalibur, yeah, won't argue its a nice ship

. Supposedly, either in the movies or at the end of Season 4 of Atlantis they will be introducing the 'Phoenix', which may be a Daedalus-class but there is some speculation it will be a completely new design, though I personally find this unlikely.