Native compiled install sets for X11R6 are not available for port-mvme68k
However, you should be able to download te X distribution sets for one
of the other m68k-based ports (eg. mac68k or amiga) and get them to
work on mvme68k (minus the server set, of course).

Alternatively, you can get hold of the latest X11 source distribution
from your favorite ftp site and just build it. This was last tested on
mvme68k-1.2 with X11R6.1 and compiled straight out the box :-)