Gios Compact Pros have relatively short top tubes, but steep seat tube angles so they fit longer than they might seem. Eddy Merckx steel frames probably have about the shortest effective top tubes because of their relaxed seat tube angles, but good luck finding one. Used Merckx frames come up for sale on eBay all the time but can be pricy.
For your budget, your best bet might be to find an older Japanese sport touring frame such as Miyata, many of which have relatively short top tubes, particularly in larger sizes.
Those people recommending Surlys don't understand frame geometry charts very well. Surlys have relatively long top tubes and short head tubes, probably the opposite of what you are looking for -- unless you don't mind using a stack of spacers about 4" tall below your stem.