Alright, my 2 cents. The first time that I looked at this picture, the frame reminded me of 1985ish era Panasonic Japanese road bikes that were sold in a 17" mens frame with 27" wheels. The only difference was that the top tube dropped down at about a 45 degree angle from the head tube, then was horizontal until the seat tube. As far as I remember, and I could be quite wrong, the front brake was a Dia-Compe center pull and the rear brake was a Dia-Comple alloy side pull. I have never seen a Nishiki withe this frame design, but it is somewhat similar to the mentioned Panasonic design.
Skyerocker-I agree with you wholeheartedly about Maillard helicomatic hubs. I sold Treks and Peugeots that had them, and never remember having any significant structural problems whatsoever. The 'freewheel/cassette' came off the hub very easily, inidividual cogs were easy to replace , axles wore OK. I really don't understand why the entire system is so badly maligned. If I ever find a reasonably priced 1985ish Trek 720 touring bike with the helicomatic system, I would not change the wheels for any reason. Just my 2 cents.