I recently had the opportunity to ride a funky bike with super long cranks. I was doing a small repair to a custom lightspeed. So picture this. A gentlemen 6'3'' with a 72 cm seattube with 220mm bullseye cranks and one of the super oval chainrings and all the latest techno gook. Well, I did take is for a small spin. That is a big lever so you can push a big gear abet slowly. It kinda feels like you have one gear even if you shift it around. Of course the pulsing from a chainring about three inches high and 10 inches long wasn't that fun. I have to agree with Sheldon somewhat here in that if one is just crusin' than maybe longer cranks help to generate more force at the same slow cadence but at maximum aerobic output round rings, normal cranks and the correct gearing will achieve a better results.
Dave Bohm Bohemian
Oh, I remember him well, he was an original, and a monomaniac! When
I first knew him he didn't have the Paramount, he had a modified
frame, I think it was a Hercules. he had cut out a section of the
seat tube, jacked up an automobile, then lowered the car onto the
frame to "adjust" the geometry, then brazed the now shorter seat tube
back together.