Open package manager and search for "wmctrl". Its a tool which lets you control x windows from the command line. It is actually suprisingly useful. Install it.
Next you want to use your favorite text editor to create this script:-
if wmctrl -m | grep -q '"showing the desktop" mode: ON'; then
exec wmctrl -k off
exec wmctrl -k on
Save it to your home directory as showdesk.sh. Open a terminal up and make sure you are in the same directory as showdesk.sh. Use su to get root access and chmod 755 to make it executable. You should now be able to execute the script using "./showdesk.sh". If it works then you can just make a shortcut to the script and fire it when you want to show desktop.
To give credit where it is due, I 'stole' the script from this page which I found when googling for wmctrl: http://rox.sourceforge.net/desktop/n...65e8abfdcf22cb
Good luck, let us know how you get on. I have to confess, I havn't actually tried this script myself as I am on my windowze laptop as I write this. However it looks like a good shot to me - and I am sure that wmctrl is availiable in the FC repositories.