If you are going to do a ground up resto on a car, a bit of rust doesnt make that much difference in the whole budget, it only amounts to a week of extra time (if that) in fixing the rust, and with rarer cars (like all the cars I have) its just par for the course because you are just lucky to get your hands on one, rusty or not. (normally rusty)
People will either have the skill set to fix the rust or take it as an oppurtunity to learn how.

$1400, thats less than a Dellow 5 speed conversion, less than I sold my H150 LSD for, 1/4 of what it cost to paint my car, its $400 less than I paid to get my seats re covered, its the price of a new set of wheels and tyres.