The Raspberry Pi page on the FreeBSD Wiki links to a blogpost about setting up xorg on the Pi. That post was written back in 2013 and most of the information there seems to be out of date.
I set up X on a Pi at the end of December 2015, this information is up to date for r292413. pkg is now available on arm images so there is no need to build everything from ports, considering tools like tmux could take 6 hours to build on the pi itself this is a huge improvement. I installed the following packages to get X up and running on the Pi:
# pkg install xorg xf86-video-scfb i3
The Pi isn't able to auto detect the X configuration, I looked for a while for a config that would work. Eventually I dug the following one from a mailing list post. Place the following into /etc/xorg.conf:
Section "Device" Identifier "Generic FB" Driver "scfb" EndSection Section "Screen" Identifier "Screen" Device "Generic FB" Monitor "Monitor" SubSection "Display" Depth 16 #24 32 EndSubsection EndSection
With a minimal .xinitrc I was then able to start an X server with i3: