Thanks for the help, Hanchuan, I got it to work this afternoon.

I think my configuration was OK, since it's supposed to default with openGL support, but I added the option to force that anyway and it didn't solve the problem. 

As far as I can tell there were 2 problems with my setup that I corrected:

first, in the qmake.conf file that ends up installed in /usr/local/Trolltech/Qt-4.7.3/mkspecs/linux-g++-64
the line
QMAKE_LIBDIR_OPENGL   = /usr/lib64
was previously      
QMAKE_LIBDIR_OPENGL   = /usr/x11/lib64

which isn't a real location for me.

second, I also tracked down a broken link at /usr/lib64/libGL.so  which was pointing to a nonexistent library

I can only guess that these both stemmed from the yum install of the mesa-GL* packages  ??  

I hope this helps anyone who may end up in the same situation!

-Brian