Jumping in on the tail end of this discussion, I have several 50's & 60's British bikes with unequal length brake reaches, and also a pair of early Cinelli's with unequal Universals. I have always accepted Norris's explanation of alternating wheel size and mudguard installation as being part of the rational for this... also, I have heard the theory of different braking pressure on the front and rear wheels being desirable, which also sounds acceptable.
BUT, I have always wondered why my 1986 fancy lugged Condor has the same affliction, having been built at that late date?? Perhaps Norris's explanation of it being a customer ordered feature would apply... I do find it a bit strange on such a late (but still on topic, I think) manufactured machine that I thought was much older when I bought same.
Ciao -- Nelson Miller // Seattle, WA // USA