The Zeintop replaces the trunk, and the one I posted only covers the clamshell. But I think it gets really close, and you might be able to order it without the windows (but I don't why you would want bigger blind spots.)
After looking again I think it is most likely a custom top. A few spec boxster guys do make there own hardtops out of fiberglass. Just look at the third picture, and how the top replaces the clamshell to save weight, and the oversized braced window. I can safely say I have never seen the one pictured for sale anywhere.
