Join Date: Jun 2013
Location: Cedar Rapids, IA
Bikes: 1997 Rivendell Road Standard 650b conversion (tourer), 2010 Rivendell Roadeo (gofast), 1988 Schwinn Project KOM-10 (gravel/tour), 2013 Foundry Auger disc (gravel), 2015 Specialized Fatboy (MTB/winter)
There are plenty of "flat bar performance" bikes out right now. They're a road frame with hybrid controls, so they're a little faster than a hybrid bike. The Novara Express, Specialize Sirrus, and Cannondale Quick are examples.
For the most part, flat bar controls are different than those for road bikes/drop handlebars, because the two styles of bars have different diameters. So if you're looking to convert a Cross Check or any other drop bar road bike, you'll be tossing or selling the shifters/brake levers and finding new ones.
Converting a drop bar bike to flat handlebars can result in a fast, comfortable bike. But it's not cheap or quick.