Yeah, I missed that part, but you can get a Rail 52 in a disc configuration. I know I've seen rail 52s as disc wheels on that website; they may offer it as a custom build.
November is coming out with a disc specific carbon rim called the Range. They might be taking orders for them now.
November Bicycles: Race smart. - November Bicycles Blog
Just found this blog post. I think it's going to be a while before the range is released. Drag.
November Bicycles: Race smart. - November Bicycles Blog - Range*Update