I believe that the KDE changes described here
will have significant implications
for BSD users. Essentially, Slackware build scripts share similarities with the ports system although they lack dependency checking and automagic source code retrieval.
I recall the OpenBSD developers initially shelved KDE4 development as qt4 was having teething problems but I think that qt4 has stabilized This also can not be good news for PC-BSD.
I wonder if the BSD's would consider collaborating to develop their own desktop environment, possibly forking something like xfce 4.6-4.8? Then the only major hurdle would be video drivers for currently manufactured motherboards and video cards.