Nice writeup Carlton...I know that feeling you had. About 6 or 7 years ago I ran across a letterhead with cover on ebay right when it was first listed for Green's Nebraska Indians and the letter had content about his all Japanese player team he was forming...I agonized over it the whole week..set my snipe and watched what I thought was an impossible to beat snipe get outbid. It sold for $705. Devastating at the time, it was all I could think about, I could not believe that my crazy, insane snipe was topped.
Partial good news is that a few years later I managed to find the cover envelope...listed wrong with no mention of baseball at all and I snagged it for $10. I've not seen another letterhead before or since though.