The list is there as /etc/X11/xkb/rules/xorg.lst -- a symlink pointing to base.lst. I think what's happened is that the file has changed, and the vxkbset script hasn't; but I haven't looked at older versions or notes to confirm this.
In any case, replacing the function "build_menu_modelx()" provides something that works minimally, but the script still causes at least one problem and was tested only once!Several keys on my keyboard didn't operate normally until after a reboot, but then things seemed OK. I have to leave this alone for now and go on with something else. I post the work so far in hope that someone can continue at least a bit further. Hint: Read the new function side-by-side with base.lst and you may see a way to read lists of variants, etc., from xorg files so those lists can be removed from the script itself..
Most users should wait for an approved version and not do this now, but if you have a need for it now or are kind enough to look into it further, here's the interim replacement for /sbin/vxkbset function build_menu_modelx():
##################################################################
# SET KEY MODEL
build_menu_modelx()
{
STATE=2
while read KNAME KDESC ; do
[ -z "$KNAME" ] && continue
[ -z "$KDESC" ] && break
case $STATE in
2)
[ "$KNAME $KDESC" = "! model" ] && STATE=1
;;
1)
[ "$KNAME" = "!" ] && break
STATE=0
echo "'$KNAME'" "'$KDESC'" '\'
;;
0)
if [ ! "$KNAME" = "!" ] ; then
echo "'$KNAME'" "'$KDESC'" '\'
else
break
fi
;;
esac
done
return $STATE
}