Trevor,

Found what I did wrong with xmodmap.

I had to be run in an xterm that was sourced from the remote machine and displayed on the MBP. I had started an xterm on the MBP SSH'd to the server then ran xmodmap -pke.

Mark,

Sounds like good advice. I once, for about eight years, used SUN workstations at work. It seems most of what I learned has decayed or been superseded since then. Tonight I learned that the Xquartz project is setting things up where all that's needed is to start the remote program and automagically X is invocked locally to serve.

Currently when I SSH to the server, and start an app, I get a generic X herringbone screen that obscures the mac desktop. I don't yet know if that is normal, of If the remote app should just float.

Now that the .Xmodmaprc is sorted out, the command...
ssh me@remotecomputer gnome-session gives me a full ubuntu desktop. Good enough for now.