None of the Lumens Factory D36 (turbo) lamp assemblies will fit: They require a head that's 45mm wide, while the 6M's head is 42mm. Even if they would fit, there's no 3.7V (4V) version; you'd have to use a 9V model, powering it with two small RCR123A cells (making it less bright, less long-lasting).
There is one 9V lamp assembly that will fit, though the fit is vertically tight: RICO Alpha 9. It's my favorite D36 lamp: bright, floody, and efficient. I use an Alpha 9 in my Wolf Eyes Rattlesnake.
The Alpha 9 lamp is sold by several paintball-supply dealers in Asia.