Gordotrek, I think this frame is too small to be the answer to your mystery.

This thing has been sitting around a while. I decided to throw some parts on and see how it rides, but I am having a devil of a time fitting a 27.2 seat post. I pried the ears apart but still too tight. I have been going at it for a while with a flex hone and I can get the post in about as deep as the lug but that's it. Starting to wonder if I have an oddball that takes a 27.0. Of course I don't have one on hand to try. I have a cutoff from a 26.8 and it fits loose. Any opinions?

I now have a small crack below the lug split. Not sure if it was there before or if it's the result of my efforts. I don't think it's enough to worry about, but I am leary about more prying.