Recently I had a scenario where I wanted to disable all of the menu items using an MCX for some NetBoot clients. To do so, I ended up building a custom MCX. To do so, first open Workgroup Manager and click on the group in question. Then click on Preferences and then the Details tab. Next, click on the + sign and browse to /System/Library/CoreServices. Next click on Menu Extras and click on the pencil. Here drop down the Always disclosure triangle and click on the New Key button. From here, name the key with menu item in question (or create multiple keys) and set the Type to Boolean and the Value to False. Keys that you can do this with include:
