Right now, individual playlists, tracks or albums are not available as 
freely placeable menu items.

For what you want to do, you can, however add a custom action (and 
mark it "global", so that it becomes available as a menu item as well) 
with this AppleScript snippet:

tell application "iTunes" 
play (1st playlist whose name is "iTunes DJ") 
end tell

You can add custom actions at Prefs > Mapping > iTunes > Select 
"Custom actions…" from the drop down.

Best regards, 
Felix Schwarz