Well if you are running a real operating system (as opposed to ms-windows) you can always use xfig ( there is a windows port called winfig). The nice thing about xifg for doing plans is that you have the option of editing the sizes and positions objects by typing in the values. Very nice for geting things exact ranther than trying to positon the mouse exactly where you want
I have a panel template in xfig that has buttons and joysticks on it