Well, and WebObjects ;-) I think gnustep-web still targets being a 1:1 WO 4.5 clone, but they can probably tell you more exactly. SOPE doesn't, we don't aim for full WO compatibility anymore but rather enhanced WO concepts in significant ways. Eg we introduced a lot of concepts from Zope. Of course it still almost completely WO API compatible.
And a real-life application of GNUstepWeb.