I got a black KL4 from a Scout Light, and several more online. My source has dried up. The black KL4 is available, just hard to find. I don't have any more for sale. Put one on an E2D body, and another on an E1E-BK. Both have the Z68 tail cap.
oldgrandpajack
PS: The latest version of the KL1 (TIR Optic) is also available in black. Again, they are hard to find. I don't have any more for sale. Also put one each, on an E2D and E1E-BK, but with Z61 tail caps. The Z61 makes it easy to differentiate between the KL1's and KL4's (with Z68's), since they are so similar in apperance.