I was going to try to hack the vncviewer app so I can hide its toolbar using gconf. The existing gconf setting don't seem to work whether set to true or false, and there is some bogus inverse logic there. I don't need the toolbar and it annoys me.

While reading the source, I found that the --lockdown option does disable the toolbar, that's good enough for me.

Apparently pressing "volume up" or "volume down" brings back the toolbars, and pressing fullscreen hides them again (with --lockdown). Nice. (also volume up + click gives right-click, volume down + click gives left click).