A good point KCT1986, I hadn't thought through the rest of the requirements.

Furthermore a longer cage would only solve the capacity (wrap) issue with the 740x derailleur. The short body of the derailleur would limit it's ability to get under a larger cog than a 28T (from memory). This would be less than ideal for a touring bike so scratch that plan.

FastJake's other idea of Campag 10spd shifters which pull an almost identical amount of cable to regular Shimano 8spd shifters is still a workable solution though.

Cheers,

Cameron