xdm with shadow support can be found in xappl1 as xdmshad.tgz, as I didn't 
want to start a xbasis7 disk just for that.

xsprea21.tgz can be found in xextra4, as I didn't want to start a xappl5 disk
just for that.

The xextra series can not be installed with the boot/rootdisk (no menu item
for that). You have to install that afterwards with 
sysinstall -doprompt -series xextra

The expert mode is still buggy, especially with debug turned on, some sed/fgrep
get confused by the extra output and that results sometimes in malfunction.