MoreDesk allows you to organise your windows on over a space which is
larger than the normal desktop. It does this by creating a grid of desktop
spaces and by allowing you to select which of these is the one you
are currently looking at.
You can easily move windows between desktops and get a view of the entire
desktop space. You can even have different sets of pinboard icons and a
different backdrop image for each of the desktops.