Here are a couple that might at least be worth a look. The brown Schwinn is billed as a "single speed," but it has the double crank and the freewheel, so you would just need to throw a couple of cheap derailleurs and a longer chain on it to make it "geared."

The Shogun looks like it would be the best fit, and would just need a cheap set of drop bars. You could reuse the brake levers.

https://atlanta.craigslist.org/eat/bik/5435403456.html
https://atlanta.craigslist.org/atl/bik/5512262747.html
https://atlanta.craigslist.org/atl/bik/5499380753.html
https://atlanta.craigslist.org/atl/bik/5469152440.html