Epicus07,

Looking at a picture of an '83 Trek 400 at vintage-trek.com, I don't see any braze-ons for a rack A bolt-on rack is usually preferable to a clamp-on rack for touring. http://www.vintage-trek.com/images/t...83/83Trek5.jpg

The rims you have should take 28mm tires easily. I have 28mm Continentals on my commuter, and I like them.

I can't speak to how much fender clearance you'll have... if you're converting from 27" to 700c, I'll guess and say you should have room for 35mm SKS fenders.

The e-Bay wheels look fine... but I don't know anything about that rims manufacturer.

You can get new, nutted, long-reach dual-pivot brakes from Velo Orange. (Ack! Their website seems to be down... look under brakes at http://www.velo-orange.com/ )

Good luck with your renovation

Edit: Ack again! Forgot about hub width!