The command that finally worked
xinit xterm -- /usr/bin/X -br :0.0
For some reason, this command also ran the window manager (sapphire in this case).
Perhaps it has to do w/ .xinitrc:
aterm & xterm & Eterm & sapphire
The .xserverrc doesn't matter, and could be simply the default:
X :0
[as specified in the init(1) man page]
