macdonaldz

http://www.smallrig.com/SMALLRIG-Manfrotto-Dovetail-Clamp-1716.html If you unscrew the wingnut far enough i'd think this should work for top loading because theres no dovetail guide on the fastener side.

why don't reduction rings work? does your anamorphic extend more than rubber bellows allow? they generally have a good 4 or 5 cm of extension/compression.. i've never seen bellows create a noticeable push on lenses with extending fronts (old standard speeds is what comes to mind)

petit cinevision rebadge?   http://www.ebay.com/itm/Anamorphic-Lens-Moller-Anamorphot-32-2x-CinemaScope-/231017421703   wonder if the REX prefix has anything to do with the bolex REX series of cameras..

  a friend of mine used this website to have some models 3d printed. i intend to use them for printing a system to make dual focus single focus (similar to what you're doing i think.)    http://www.shapeways.com/

lens alignment issue in the anamorphic attachment i would think. the petrascope i have illustrates pretty clearly how misalignment between cylindrical optics renders everything unfocusable. i imagine anyone with any apefoscope could say the same thing (i.e. get something in perfect focus - rotate one of the elements as little as you possible can (( <1 degree)) = everything soft)

Petrascope 1.5x Bell & Howell Filmorama 2x (not the same as the integrated projector anamorphic)

picked up this guy on ebay a few weeks ago. glass is in immaculate condition. super lightweight. no focusing helicoid - 2 separable optics and a set screw to retain them. came with a mounting bracket that i epoxied a 67-58 stepdown onto and  screwed a 52-67 step up onto it and the plastic 50 canon.   maintaining alignment is a pain but can create some cool mesmerizer effects. no focus marks. minimum seems to be about 4'8"   words from tony - "one they did had a grove cut out so you could move the 2 optics closer together or apart. losen the screw and push in or pull out.. you will then have to orientate the front optic so it is sharp very fiddly but quite good glass on some of them [...]  they made many different sizes it was made in a fot shop in south london in the 1970s so kind of hand made nothing was standard"         pic of setup     2 flare tests           charts   w/o petra on canon plastic 50mm 1.8   w/ petra - taking lens must be focused closer - may have some kind of built in diopter as it doesn't see to like infinity that much

I've been thinking for a few weeks now of developing a similar device but purely mechanical.   It'll be two alternately sized gears ganged together on a single shaft to accomodate conflicting focus throws and an offset gearbox to reach the taking lens. Most likely rod mounted. Alternate sized gears for taking lenses would have to be available obviously but 3d printing could facilitate that.   see attached where green represents anamorphic, blue represents taking and purple represents ganged gears to match throws. yellow 1 is idler and 2 is inversion. they would be on an articulating lockable swing away arm.