A workscreen permits to display a set of workspaces on several screens. In xinerama mode, when a workscreen is viewed, workspaces associated to all screens are visible.

The first workspace of a workscreen is displayed on first screen, second on second screen, etc. Workspace position can be easily changed. If the current workscreen is called again, workspaces are shifted.

This also permits to see all workspaces of a workscreen even if just one screen is present, and to move windows from workspace to workscreen.

You can use this module with the following in your xmonad.hs:

import XMonad.Actions.Workscreen
myWorkspaces = let myOldWorkspaces = ["adm","work","mail"]
               in Workscreen.expandWorkspace 2 myOldWorkspaces
myStartupHook = do Workscreen.configWorkscreen (Workscreen.fromWorkspace 2 myWorkspaces)
                   return ()

Then, replace normal workspace view and shift keybinding:

[((m .|. modm, k), f i)
     | (i, k) <- zip [0..] [1..12]
     , (f, m) <- [(Workscreen.viewWorkscreen, 0), (Workscreen.shiftToWorkscreen, shiftMask)]]

For detailed instructions on editing your key bindings, see the tutorial.