Sure Draw for Glocks

Here is the text from their website:

Sure-Draw's momentary safety device for Glocks provides the solution to a long-known problem - reducing the chance of negligent discharge. When the user's thumb presses and holds Sure-Draw's safer action inward, the weapon will NOT fire. Release the safety, returning to normal grip, and the weapon is ready to fire. 

Sure-Draw allows the user to holster their weapon with confidence.Sure-Draw features a new manual of arms in which the user rides the safety with your thumb as you handle the weapon in a safe condition and insert into the holster. This avoids the downside of current safety designs of many pistols that may inadvertently be left on in a moment of stress or in a tactical situation. No matter how hard the trigger is pulled, if Sure-Draw is engaged the gun will not fire. As soon as it is released the weapon is hot again.

--Glock is my daily carry. I would try this.