Nowhere near the system with this now, but I think this is the "little script" I actually used. It's a JSscript, so needs to be saved as e.g. mrsa.js, and I always throw these things in c:\windows:
I add that as an ADUC context menu item via another script, but that's a bit too me-specific and wrapped up with other stuff to post here. It's not hard to do manually though, use ADSIEdit or SysInternals ADExplorer to drill down to here:
dN = WScript.Arguments.Item(0);
ss1 = dN.split(",");
ss2 = ss1.split("=");
wsh = new ActiveXObject("WScript.Shell");
wsh.Run("c:\\windows\\system32\\msra.exe /offerra " + ss2, 1, 0);
CN=Configuration -> CN=DisplaySpecifiers -> CN=409 -> CN=computer-Display
Now edit the "adminContextMenu" attribute and add an entry:
Because I do that shortly after a dcpromo it safely assumes there is one existing entry (beginning with "1"). If there were two entries there already I'd change the "2" to "3" etc.
This basic and very useful context menu item principle works on other key objects in ADUC (e.g. Users).
I'm not sure what happens if you highlight several computers and invoke a script, because I never needed to do that and I've had better things to do on rainy days. Suspect they'll be presented to the script as additional arguments i.e. WScript.Arguments.Item(1), WScript.Arguments.Item(2) and so on.