The work of Sun Boxiang on improving wxUniv and notably wxX11 port has been merged into the trunk. This was mostly a bug fixing project and as the result of, many more unit tests now pass in wxX11 test suite than before, we're down to "only" 16 failures in 539 tests compared to 80 out of 308 before the project beginning. One new feature also implemented during this project is the new implementation of wxClipboard for X11. See Sun's summary of his work for more details.
Unfortunately there still remains quite a bit of work to be done before wxUniv can really be considered to be ready for general use, but at least know we know better what is missing or broken. In wxX11, there is some major work to be done on event loop code refactoring, to allow reusing the same logic as for the other Unix ports. We should probably also switch to using Cairo instead of the old style X11 drawing functions. And at wxUniv level, we really need a better theme with nicer appearance.
Unfortunately we, the current wxWidgets developers, just don't have any possibility to work on it, so there is no time frame for any of the above, but any contributions from people interested in using wxUniv (e.g. for writing applications with a particular appearance using a custom theme) would be very welcome!