Well … I found out that OpenDarwin v7.2.1 did not include X11 with it … I found these instructions on Google:

GET X11:

ftp http://www.opendarwin.org/downloads/7.2.1/X11-x86.tar.bz2

cd /

tar -jxpf {path_to}/X11-x86.tar.bz2

(note: this will only have twm, which is pretty lame. Darwinports will fix that for you.)

This ought to get me back to exactly where I was with OpenDarwin v7.0.1 … so then next I’ll be trying Darwinports.