Focusing E-Mount For Ultrafast Lenses

There are a variety of old ultrafast lenses cheaply available. These lenses, usually marked between f/0.75 and f/1.6, typically have no aperture iris, no focus mechanism, and a giant external screw thread intended for mounting. They generally can't focus to infinity even on a mirrorless body, and IQ is scary soft, but sometimes that's a feature....

Anyway, I originally mounted these lenses by gluing an M42-to-A-mount adapter on the back (as I described in my Instructable, http://www.instructa