Friends: Just listed a 54cm c-t Mirella frame and fork. (200235477587). I am very closely associated with seller (me). Based on parts (not included) I figure it is about 1970 - 71 (pat 1970 Campy derailleur). Nice workmanship and details, no idea of tubing. Based on components and workmanship I would say decent tubing...but it takes a pretty small seatpost, 25.4 or so (not excatly sure). It is too small for me, so I am keeping the parts and selling the frame. If anybody has something similar in 55 - 56 c-c, clue me in, I might be interested.
Also check out my other listing (stunning, slightly OT frameset)
Cheers from hot and steamy: Dallas, TX, USA, Earth Clyde "Mirella Movin'" Putman