The LX2 should produce enough light for what you want, but keep in mind that it's a bit over 5 inches long, in case that was your upper limit. Also, the LX2 was not designed to tailstand, so unless you modify the light yourself in some manner, you'll have to constantly hold the light aimed at the ceiling.
If tailstanding is indeed desired, you might look at something else, like the Fenix PD30, Quark 123^2, or any number of other comparable lights on the market. Or if you want to stick with SureFire, and don't mind the little extra length (5.4 inches - same as the LX2), the E2DL should give you about the brightness you need.