Can you help to identify these frames, bikes or parts?

Hey guys

Today I got the chance to buy the following bicycle. I was in doubt for a long time, but didn't take it. I'm still in doubt to buy it, so that's the reason of this post.

First off, the frame has no decals. The paint is very good. It's only stamped "56" on the bottom of the bottom bracket (framesize) and the drop-outs are stamped "Gipiemme".
The tubing is Columbus Gara.
Set of pictures of the bicycle: http://imgur.com/a/hEVVy

Remarkable facts about the frame:

• the lugs are pantographed with an M (not Merckx, not Moser). Anyone who recognizes these M's?
  
  

• the toptube is crimped, Colnago style
  
  

• the downtube starts rounds, becomes oval in the middle but ends round again

• the seattube is cutout for the rear wheel

If anyone has a clue or has seen some of these elements on frames before, please let me know! I would like to figure out what this frame is.