[...]

> It is under IRIX and RedHat Linux, maybe others.  Though in Linux it's
> just a link to /usr/X11R6.  

It's actaully quite easy to change your xf86site.def to do this.  The only
lose is that you have to rebuild a lot of source and your X server.  This
is lengthly process (even on my Pentium Pro 200), and trying to not build
part of the source tree often requires numerous changes to several *.cf
files (the XFree86 project certainly didn't make this any easier).

> > Maybe that's just because I "grew up" inside an X11Rn directory with
> > /usr/X11 a symlink to wherever X11 happened to live (it was a devo
> > environment, what can I say?).

This seems kind of backwards to me.  If you want to keep multiple versions
of X on your machine, you would *want* to have X configured to live in 
/usr/X11.  With the current /usr/X11Rn scheme, having /usr/X11 be a symlink to
the version you want to run may allow you to keep your $PATH and ld.so.conf
X revision neutral, but not imake.  Managing multiple releases of X would
*truely* be easier with X11 pointing to the release (X11R5, X11R6.{1,2,3},
whatever), but having the project root be /usr/X11.  I think BSDi may do 
this (not sure, never checked).


Carl