Hi,
x2goclient: I suppose no... x2goplugin: should be possible (like any other ff plugin)
Is this ff plugin ready fore use. I learned about it at a talk by Heinz Graesing (2010-05-28), but I couldn't find a place to download it.
since kde4 there is no more debian/ubuntu package called kcontrol. The replacement of kcontrol in kde4 is called systemsettings (name of the .deb package).
I am not sure enough if the admin GUIs will plug into systemsettings in the same way as they do with kcontrol. If so, the developers might provide a package update with the respective dependencies.
For you a work-around could be to provide a dummy kcontrol package with equivs-build (check equivs package on Ubuntu/Debian), just to satisfy dependencies in the x2go packages. However, this is untested...
I managed to solve the dependency problem by creating a meta package. However, most admin tools are not working because x2goldaptools.conf is missing. There might be no such file as I am running only a x2go-one server. I'll figure that out when I try a full x2go server installation someday.
Alex