The hardest part was getting the ash cap off. Then I just used a dremel to cut off about 15mm of the front of the passthrough. It is a standard 901 USB complete with pressure switch. The led board is epoxied to the bottom of a flashlight lens and glued to the top of the pipe. Rough up the lenscap to diffuse the light and you're in business.
I think I'll work on a longstem version too.