finders - hacking solutions anyone?

[Robert Monaghan <rmonagha@xxxxxxxxxxxxxxxx>]

I find the subject of ultrawide finders to be quite interesting,
particularly after pricing some commercial examples (aargh!) ;-) The idea
of spending $450 for a finder is disconcerting, but even the russian 21mm
and leica finders cost more than some of my 35mm SLR lenses (nikkors at
that!)

has anyone come up with any decent finder alternatives? Ralph 
Fuerbringer's point (re: $450 linhof is similar to 0.42x superwide adapter)
suggests this might be one low cost way to create a suitable very wide 
finder? 

Unfortunately, the Ikelite flash shoe mount finders would be ideal, except
they aren't very wide (like 20mm?) and they _are_ painted dayglo orange
and they are pretty big and still circa $100 US. These finders are used in
scuba diving underwater, where you can't use a regular viewfinder (e.g. on
nikonos) for lack of wide angle coverage or ability to get close while
wearing a mask. The eye relief on these Ikelite finders is tremendous -
like five or six inches - and they support a variety of standard 35mm lens
masks and also come with custom plastic screens you can scribe your own
pattern as needed. Grids show typical barrel distortion, but they are
pretty accurate. Gizmo is size of a small lemon; price was around $100 US
last time I bought one (albeit some years ago)... 

I have been experimenting with a Topcon rectilinear fisheye lens assembly 
from a digital light processor - the projection TVs that use Texas 
Instruments mirror chips to project big screen bright tv images. fisheye 
is about 1 1/2" in diam. and very wide angle coverage, projects from flat to 
flat screen (e.g., pretty rectilinear) and bright (no iris though) - 
coverage is small, to match digital chip, but relatively close to the eye 
pupil size (7mm etc.). Just another alternative for finder hackers to 
consider? (these are local surplus examples, any others out there?)

I suppose one of the new 0.42x or similar mutars would be useful, as 
ralph notes, with the right masking. I have found at least 2 types, the 
old solid glass ones are heavy and big, designed for 35mm and 2 1/4" 
cameras; the newer ones (often claiming to be "autofocus" and "titanium" 
and "macro") are much lighter and cheaper ($20 used from Goodwin photo 
for last used one I bought) and might make decent finders at that? 

anybody got any good examples of finder alternatives that work for panos 
and ultrawides without leaving that "empty wallet" feeling? ;-) Thanks!

regards bobm