Originally Posted by Loch
I thought about a front derailluer, but the seat tube size is odd and it would be difficult (probably not impossible but difficult). I have been running the 53/39 setup for awhile on most of my folding bikes. It works very well for me as most of my riding is on the big ring. Occasionally I'll come to a hill that needs the 39T and I shift it with my foot. It works well for me, I toured England and Ireland with a setup like this and really the only drawback is that it takes more time to shift it back up and your finger gets a little dirty.
I like the simplicity of this system, Loch. It seems to me that the key to the success of this method, apart from the mechanics of shifting, will be achieving a low enough usable gear on the large chainring and a high enough usable gear on the small chainring that one doesn't need to change from one to the other very often. For my legs, gear inches of 35 and 65 would probably fit the bill. I suspect you are a stronger rider than me. What gears are you running? Also, is the 'foot change' a very delicate process? Can it be done suddenly, when required? Do you ever miss?
P.S. Beautiful looking bike.