Projector beam lens? I just had one in my hand last night (it's at home now, I'm at work) that is mounted on an eighty year-old brass 3D flashlight -- given to me recently by a kind CPF'er, I've been admiring it for its old-style construction (mostly a lot of thin curved/folded/bent brass sheetmetal) and its apparent collectability, but now I will have to try shining a bare LS beam through it to see how it goes.
The dome is a heavy, sturdy piece of solid glass with a modified cabuchon shape. There is no reflector so I presume the beam was of sufficient magnitude and intensity all by itself (the internals don't work now so I never saw it). Will post pics of both it and whatever beams I get out of it if they are worthwhile, as soon as I get home (if I remember)...