This just in -- the 89-26 "lightweight" fender set from those artists of chromed steel at Wald will fit on a 700c touring/cross bike with room to spare, despite being advertised as a fender for 26" wheels.
As proof, I submit my much-loved Bruce Gordon, freshy gussied up with twenty bucks (seriously!) of Kentucky chrome. Your bike may vary, but my only modification from stock was to drill a second hole in the front fender stays and lop off the original hole that was intended for the front axle. This allowed me to bolt the stay to my fender eyelets and maintain a good fender line. The rear mounted up with the original, factory drilled hole once I added some big washers (since, again, the hole was intended for an axle, not a small bolt running to an eyelet.)
My set didn't come with all the hardware I needed -- there wasn't an L-bracket to bolt the front fender to the fork crown or a bracket to attach the rear fender to the brake bridge. It seems those are sold separately, at astoundingly reasonable Wald prices -- about two bucks for a set with everything you need. I had spares in the garage from old fenders, so I just used those instead.
I haven't test-ridden the setup yet (note the computer mount dangling in the front wheel that needs to be addressed first), but the fenders look like they'll provide more coverage (and definitely more toughness) than the Planet Bikes they replaced. I'm kind of stunned that you can get such a nice looking metal fender with rolled edges for so darn cheap. I would wonder if there's a catch in terms of rust or long-term reliability, but I know my grandparents' Schwinn DeLuxe Twinn tandem sported a pair of Wald fenders from the day it was purchased in 1967, and those fenders still looked (and performed) great when they finally sold the bike in 1998.
I confess, I also took perverse delight in mounting $20 Wald fenders on a Bruce Gordon with an XT/XTR drivetrain. Take that, snobs!