X300U with DG11 switch is the current "A" answer in my opinion.
Why not just get a good high power hand held light? Do you really want to be pointing the gun at things and people you might not want to shoot just to identify what they are? Also do you want to give a bad guy a nice bright target to shoot at as opposed to holding the light away from your body? All things to consider.
Yes, a good handheld light should be employed in addition to a weapon light. Both should be available to you. Handheld for admin tasks, WML for fighting. I keep a FourSevens Quark in my left front pants pocket at all times. I also keep a SF X300U mounted to the Glock in my holster at all times.
There are multiple techniques you can use to search both large and small areas with a WML without ever actually pointing your weapon at someone that doesn't deserve it. Additionally, some things should have guns pointed at them as you attempt to acquire and identify a threat prior to dealing with it. Now, I don't know about you, but I shoot much better with two hands on the gun rather than one on the gun and the other holding a handheld light. If you are searching with a handheld and you have to go loud, that's one thing. But, don't limit yourself. Drop the damn hand held, and get two hands on the gun and go to work.
Did you ever try to shoot and move in low light using a handheld light? Its hard. Add a moving target and its even harder. Trying to aim two independent things (hand held light and a gun) at a moving target that has the potential to kill you, is distracting to say the least. Having a WML lets you aim the gun and the light together, increasing your chances of tracking the target and getting hits where you want them.
Finally, not using a weapon light because you are afraid to "give your location away to bad guys" or "give bad guys a target to shoot at" is silly. What would you do under daylight conditions? Are you granted a cloak of invisibility when the lights are on or the sun is up? No you are not. Is your body not something that will give your location away or give bad guys something to shoot at?
Use the same tactics, techniques, and procedures for the proper use of cover and concealment day or night. Do not rely on darkness. Shadows don't stop bullets. Hard cover does. Learn to identify positions of advantage and use them.
Get a WML. Get a hand held. Get trained. Learn how and when to use both.