Depends on your definition of "road bike". If you simply want to ride onroad
then there are lots of choices. Dahon Speed D7, Downtube FS, Breezers, others. But if you're looking for something more like a speedy Road Bike
, comfortably cruising 18+ mph, then you're either looking at some costly upgrades to an inexpensive bike, or a more expensive bike.
Although at $700 its over your price range, the Xootr Swift
was supposedly designed with your neighborhood in mind. I have one and love it. I haven't rideden a "regular" road bike in ages (got hooked on MTBs in the mid 80s and only recently got back onroad), but many say it feels very much like a road bike, but a bit more 'responsive'. I have the stock flat bars on mine, but I hear it takes drop bars very well so I'd expect bullhorns wouldn't present a problem. I think the OP in the Swift Folders
thread had bullhorns on his for a time, IIRC he posted pictures there someplace.
My rave about Swifts aside....brandscycles.com had a great deal on Smooth Hounds earlier this year for $600 but looks like they're sold out now. They've still got Hammerheads in the Large frame, free shipping too
. Still a bit more than you wanted to spend though.
Good luck with your quest.