Todd,
Have you tried any of the Shimano trekking style front derailers with the Sugino 110 BCD cranksets? Like the FD-M581-3 or FD-M761-3? (the -3 is the important number here) Shimano still makes nice trekking cranksets--- so the chainring size (26-36-46) can't be the problem. Is it possible the Sugino super-shift pins are getting in the way?