So I tried VirtualGL.  I installed and configured it on the remote workstation according to the instructions on the web site.  I opened a secure tunnel to the remote workstation (ssh -L 5907:localhost:5907 host.domain), started a VNC server (vncserver :7), and opened a VNC session to localhost:5907.  I then tried various ways of using VirtualGL:

With '/opt/VirtualGL/bin/vglrun runwb2', it complains that it 'Could not open display :0.'

With '/opt/VirtualGL/bin/vglrun -d :7 runwb2', it complains that 'VirtualGL attempted to load the real glXQueryExtension function and got the fake one instead.'

Any ideas?