I found the need/desire to use Xvnc options differing from the default for 
some vnc sessions I wanted to setup on some machines of mine.  I found it 
pretty easy to implement. 
 
I added a line to /etc/sysconfig/vncservers, using some sample options (for 
illustration): 
VNCOPTIONS="-depth 16 -geometry 800x600 -alwaysshared" 
 
and then modified the vncserver.init script, in particular, the line launching 
the vncserver process from: 
...] && vncserver :${display%%:*}\"" 
to 
...] && vncserver :${display%%:*} $VNCOPTIONS \"" 
 
I suppose this idea could also be extended to include display-specific 
options, say, I want -depth 16 to apply only to to the vnc server on display 
:1.  
 
I'll include a patch detailing the modifications to the init script.