I saw this post from a couple of months back, and I thought I would give my experience. I'm not sure about the VME 1 x 123 body, but my E2D incandescent head will NOT fit on my Valiant 2 x 123 body with primaries or a 17670 cell. The bump on the bottom of the incandescent module does not leave enough space with the Valiant body. It appears the Surefire body has 1-2 more threads than the Valiant body.
I had replied to this thread before The Big Crash of 2011.
It won't work: the VME bodies are designed to be used with their heads using a Malkoff drop-in. If you put a CR123a into a SureFire E1x body the top of the battery will sit just under flush with the top of the body, but, the spring at the tail cap will allow the battery to be pushed into the body and the top of the battery will sit about 3/16" below the top of the battery tube. On the VME body, placing a battery in the battery tube will have the top of the battery sitting about 1/8" above the top of the body tube and pressing it in against the spring will have the top of the battery sitting about flush with the top of the body tube. The battery needs another 3/16" clearance to work with an E-series head, but, the VME bodies don't allow this.