[Leica] M viewfinder "demagnifier"

[Harvey.Arche at jp2hs.org (Arche, Harvey)]

Peter,
Call me a dork, but my solution to this is to use a 35 with bugeyes. It's 
how I shoot my M2s. I like having all that space around the 50 frameline, 
and the bugeye summarons & summicrons seem to run a couple of hundred 
dollars cheaper. Sure its clunky and looks like hell, but it also looks so 
terribly old-school that no one would think of stealing it from you. Or even 
taking you very seriously.
Arche

Peter wrote:
Not sure what you would call it:  A minifier, demagnifier, reducer, or
what.  But it looks like the opposite of the M magnifier.  It reduces
the magnification 0.85x.  So a .72x finder would become a .61x finder,
fairly close to the .58x "a la carte" M finder.  A  .85x finder would
become the standard .72x.
 
http://www.unicircuits.com/shop/product_info.php?products_id=111

This looks like something I've wanted for a long time--a way to
demagnify the .72x viewfinder so I can see the entire 35mm frame
comfortably with glasses.  You have to order it from Japan, but they
take your credit card and offer prices in several currencies.
 
Has anybody used this device?  If so, how well does it work?  Does it
have a rubber eyepiece so it won't scratch glasses?  The picture seems
to show a ring with spanner wrench slots, so maybe not  :-(  Then the
question is whether the eye relief is enough for  one of Stephen Gandy's
vinyl stick-on eyepiece "doughnuts."

Note that this site also lists a couple of M magnifiers, but those pages
are clearly marked with a notice that due to Leica patent restrictions,
they won't sell the magnifiers to the U.S. or Germany.  No such
restrictions are noted for the DE-magnifier.

And they say that on May 8 they will make available a 1.35x magnifier
for the Bessa R, Epson RD-1 and Nikon D70, D50, D2X. 
 
--Peter