My kids tend to leave their phones laying around a bit, and I wanted to have the phone's location automatically reported to me after a period of inactivity. Here's something similar to what I did, that might work for you:
Named Task: Inactivity Timer
Variable Clear %DIMSCREEN
Wait 5 minutes
Variable Set %DIMSCREEN = 1
Note: Collision handling must be set to Abort Existing Task
Profile: Dim Screen
Context: Variable Value %DIMSCREEN Is Set
Enter Task:
Auto Brightness Off
Display Brightness 50
Profile:
Context: Display Unlocked
Task: Inactivity Timer
Profile:
Context: Button Widget Clicked (leave default settings)
Task: Inactivity Timer
Profile:
Context: New Window (leave default settings)
Task: Inactivity Timer
Each time the display is unlocked, a button is pressed, or a new window appears, the Inactivity Timer task is executed - aborting the existing timer (if it's still running), clearing the %DIMSCREEN variable, and waiting 5 minutes before setting the %DIMSCREEN variable to a value (the value doesn't matter, as long as the variable is set the something).
If the 5 minute timer expires, the %DIMSCREEN variable is set, causing the Dim Screen profile to activate - turning off auto brightness and setting the display brightness. Any activity (unlocking the display, pressing a button, or displaying a new window) will start the inactivity timer - clearing the %DIMSCREEN variable, causing the Dim Screen profile to deactivate and return the screen brightness to it's previous settings.
I don't think this will "wake up" the device with a simple tap of the screen (absent pressing a button), but it might be possible to use the new Scene functionality to make a full-screen scene that will respond to a tap anywhere on the screen, and then hide itself. I didn't have time to work with the 1.2 beta, so I'm trying to get up to speed on the whole scene thing.