If you are thinking that a flexible corridor would make things easier, you can get a dryer-vent-sized flexible pipe that is insulated... i think it is for cold air / burn air intake for your furnace .... I just looked in my utility room and mine is brand-named "flexmaster" 5in. Looks like it is basically a heavy duty dryer vent, wrapped in fiberglass batting, all sheethed in a plastic bag. 5" is the ID, it is about 7.5" OD.
As pointed out by Chillhayze, the extra space (and measly 1" insulation) would make your fridge work harder, but it would also provide lots of room for the air circulation neccessary to cool your lines for that distance.
Hmmm. In fact, maybe you run an extra tube... say, 3" diameter, inside the flexmaster tube. Your beer lines go through the inner tube, and the inner tube is also fitted with a computer fan or two forcing air up it. The cold air then flows with the beer lines up the inner tube, cycles out the top (near the taps), and returns in the outer sheath (between the 3" tube and the 5" flexmaster tube).
Just a bit of brainstorming... but now that I think about it... Iactually kind of like the tube-in-tube idea for air circ.
Keegan