I'm basically looking for Aero Peek style functionality that triggers after a certain period of inactivity. Is there any way of achieving this?
You can use scheduled tasks to execute a command (after a period of inactivity of your choice) which will call the "Show Desktop" command. Follow these steps to create a "Show Desktop" command as a file, and then create a new scheduled task which launches the file.
Alternatively, if you simply want to use the Aero-peak functionality instead of actually minimizing the windows, you can use AutoIt to create an executable to move your mouse to the bottom right corner (or wherever else your Aero-peak button is). You can then run the executable again as a scheduled task.
The AutoIt script would be trivial to complete, as you only need one single line. Just use the