I am still not having any joy running
/emul/freebsd/usr/X11R6/bin/XSuSE_NVidia_FreeBSD:

# /emul/freebsd/usr/bin/ldd /emul/freebsd/usr/X11R6/bin/XSuSE_NVidia_FreeBSD
/emul/freebsd/usr/X11R6/bin/XSuSE_NVidia_FreeBSD:
        -lz.2 => /usr/lib/libz.so.2.0 (0x401e4000)
        -lm.2 => /usr/lib/libm.so.2.0 (0x401f0000)
        -lc.3 => /usr/lib/libc.so.3.0 (0x40209000)
# /emul/freebsd/sbin/ldconfig -r
/var/run/ld.so.hints:
        search directories: /usr/lib
        16:-lz.2.0 => /usr/lib/libz.so.2.0 (abbreviated list)
        19:-lm.2.0 => /usr/lib/libm.so.2.0
        13:-lc.3.0 => /usr/lib/libc.so.3.0

On starting /usr/X11R6/bin/xdm:

...
   218 xdm      GIO   fd 3 read 1003 bytes
       "! $XConsortium: xdm-conf.cpp /main/3 1996/01/15 15:17:26 gildea $
...
   218 xdm      RET   read 1003/0x3eb
   218 xdm      CALL  close(0x3)
   218 xdm      RET   close 0
   218 xdm      CALL  break(0x25000)
   218 xdm      RET   break 0
   218 xdm      CALL  break(0x26000)
   218 xdm      RET   break 0
   218 xdm      CALL  __stat13(0x20ac0,0xefbfd8b4)
   218 xdm      NAMI  "/usr/X11R6/lib/X11/xdm/xdm-config"
   218 xdm      RET   __stat13 0
   218 xdm      CALL  getuid
   218 xdm      RET   getuid 0
   218 xdm      CALL  fork
   218 xdm      RET   fork 219/0xdb
   218 xdm      CALL  exit(0)

So things look OK, but the result is the cursor moves half way up the
screen, and there is periodic intense disk activity, and
/usr/X11R6/lib/X11/xdm/xdm-errors says

XSuSE_NVidia Version 1.1/ X Window System
(protocol Version 11, revision 0, vendor release 6300)
Release Date: 20 October 1997
        If the server is older than 6-12 months, or if your card is newer
        than the above date, look for a newer version before reporting
        problems.  Please report problems to x@suse.de
Operating System: FreeBSD 2.2-STABLE i386 
...
xdm error (pid 1857): IO Error in XOpenDisplay
xdm error (pid 220): Display :0 cannot be opened
xdm error (pid 220): Display :0 is being disabled

Has anyone got an idea on what I should try next?

Cheers,

 Patrick