Wow, I remember this thread from way back when. well biked, glad you've enjoyed the ride since then.
For the record, and for comparison, my Sugino XD2 triple got proper chainline on a 130mm-spaced bike using a 110mm bottom bracket.
The XD2 (48/36/26) is on my
Centurion Comp TA, which originally had 126mm spacing but I spread it to 130mm for the rebuild.
As for Abacus' question, a UN-54 bottom bracket is fine. The difference with the UN-7X series and the UN-5X series was that the UN-7X had a fully hollow spindle, that was a little bit lighter. I think the seals are the same between the two though.
To my understanding, Shimano discontinued the UN-7X series because of the shrinking market for square-taper bottom brackets.