I think MorphOS does already, dosn't it?
Steven
MorphOS itself doesn't offer sd, but there are 3rd party tools that offer sd. I don't use it, since Amiga-m is faster and more convenient IMHO. Also the RMB on the depth gadget offers a thumbnail view of other open screens and allows simple selection.
The sd aproach with todays hw doesn't feel as smooth and natural as on the old hardware IMHO. Fancy stuff like a rotating cube for switching screens is also a nice gimmick, but not very useful.