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Debian don't package most of ROX, but it doesn't matter because you can get it all through Zero Install anyway:
As for being a "complete" desktop, it depends what you mean. The goal is to get the desktop you want, not avoid GNOME and Xfce components on some kind of religious basis.
Free software is about being able to mix-and-match components. The Free licenses provide the legal system for this; what we need now is the architecture to make it technically possible.
And it looks like we're getting pretty close, thanks to the common standards coming out of freedesktop.org and similar groups.
Just as you should be able to install any program on any distribution (http://0install.net etc), you should be able to run any desktop application with any session manager. It's just good architecture.