I've spent a few days going back and forth trying to find an answer to a
fairly simple question -- What will it take to bolt a MC Rubinar 500/5.6
lens onto my Nikon DSLR?  

I've found a lot of scattered information through judicious googling,
much of it contridactory.  But this is what I do know:

* Due to focal plane differences, I'll have to adjust the focusing
 limits on the lens.  Big deal.
* The lens comes with either a M42 and/or a T-Mount.  (Are they
 available in either, and/or is it converted easily?)
* The lens has 4mm clearance to the camera body with a M42 mount, and
 is 113mm in diameter.
* A combination of the M42-mount and M42->Nikon converter won't clear
 the flash housing on my DSLR's body. (At least with the M42 converters
 I've seen so far)  Though I should be able to use an extension tube.
* If I slap a teleconverter onto the lens, It'll clear, of course.
* Theoretically a T-mount->Nikon converter will give me the clearance,
 if the lens has a T-mount, that is.

  http://www.rugift.com/photocameras/rubinar_500_lens.htm

These guys sell the lens with a M42 mount.  They refer to M42->T-Mount
converters but I can't seem to find one.  

  http://www.russianoptics.com/page6.html

These guys are ambiguious on what kind of mount the lens has, and seem
to treat M42 and T-Mounts as the same.  

  http://www.king-2.co.jp/bestselect/BS345/BS345.htm

These guys sell a complete kit to bolt them together, complete with
"grease exchange * helicoid adjustment being completed NIKON mount"
This should just work, but if I know what bits they used I can just bolt
them together myself.  (It'll be a fairly expensive order, too..)

  http://www.iris.dti.ne.jp/~y-tano/kizai/rubinar500.htm

This is the aforementioned kit on a D70.  It doesn't look like there's
anything other than mount adapters (T-Mount?) on there, but google
translates the page so poorly that I can't do anything other than
chuckle.

Ifound another ite which seems to indicate the lens has a T-mount ring
under the M42 ring, but I haven't been able to confirm this is the norm.  
I suppose if the answer to this is 'yes' then that's all I need to know.  

...and lastly, nobody's replied to my e-mails yet, and I don't know any
old dogs that may know either.  

So all that said, does anyone have one of these lenses on a Nikon body,
and if so, what mount is really on the lens, and what series of widgets
were needed to get them to mate?  The focal plane difference I can take
care of.

Thanks!

- Solomon