BeyerDynamic M500N Ribbon Replacement? Where?

Does anyone know where I can get my Beyer M500N ribbon replaced?  Beyer doesn't do it anymore, and my ribbon has finally flaked out.  I've never replaced a ribbon myself, so I'm not sure I could do it on my own.

Samar Audio Designs for correct ribbon type.  I don't see his white market ad anymore, but:

http://www.samaraudiodesign.com/RibbonMicMods.html

Just a note on the beeper 500.  I have one and by the sound of it assumed the ribbon was broken or sagging.  It turns out the pop filter which is a white cloth screen inside had come loose.  The glue used, had dried out and  pieces of dried glue had fallen into the space between the ribbon and the magnet structure freezing the motion of the ribbon.  I blue out the glue sideways to the ribbon and upside down, being careful around the ribbon with my breath not an air tool.  I then cleaned up the rest of the glue and the ribbon was free to move.    It all worked again and had good low frequency as well. 

Just a suggestion to make sure you have a bad ribbon.  You cant even see the ribbon until you pull the internal pop screen off the mic capsule assemble.    Just make sure its not the same problem I had before sending it in.

Thanks guys!

Funny you should mention that plastic piece, it had come loose, but that wasn't the problem.  The ribbon is sagging tremendously, and also has a small tear in it.  I wish I knew how to fix these things myself...

I second Samar Audio.  Marick is the man when it comes to working on ribbon mics!

  Last I looked at his website, Samar actually has the original ribbons and can do a proper replacement. His price seemed very reasonable to me.
  However, I have re-ribboned a M500 myself, and tho it was very difficult, the mic sounds pretty good now. Of course, I did not do it with the original ribbon material as Mark can, but just used some 1.8 micron foil, and used the top of a medicine bottle to give the ribbon some texture. It sounds surprisingly good, and I'm very happy with the results. I was encouraged by another member of this forum who said he tried it and succeeded.
  These are great mics! It's worth whatever you do to get it up and running.

our m-500 at work had a ribbon split. I sent it to jon over at shinybox. He did a great job with it.