First off dowload Always on Top (Direct link to download) which is a simple script that maintains a designated window on top of any other open window or program you have open at the time. You then select the drop down for, "On Top APM Display," from the "Tools," menu
Then you select the display icon that appears and hit control+tab while running the Always on Top Script. The icon below will then run on top of whatever program you've got in windowed mode on your computer.
I suggest putting it in the top left hand corner, top center, or left side to avoid obscuring any other menu options and pertinent information to actual game play (should you still have the menu options displayed).
Next you will need to go to SC2 and opt to run the game in the full screen windowed mode. The game will now run with the above APM indicator in the designated area while allowing you to play as normal. SC2Gears also allows you to lock the indicator in a given location to prevent inadvertent moving
It is important to note that if you do click the APM indicator you will bring SC2gears to the forefront, and while a simple click will bring you back to the SC2 window it could affect your in game experience should you be in a rather tense situation, or clicking erratically. The game should not minimize, but it could depending on your settings.
As it stands I am unable to screen cap an instance of my running SC2gears and WoL simultaneously displaying as I am on the girlfriends laptop, but I will update at the first chance I have. As best I could tell from my searching I was unable to turn up a topic detailing this method for showing your APM in real time during a ladder match
May not be the most direct solution to the problem, but hopefully you have a bit of fun with it.