Just try out a longer stem and see how it feels. As long as you don't mind the saddle to bar drop a small frame isn't the end of the world. Maybe not the ideal fit, but you'll end up with something along the lines of an aggressive road fit. Try some pics from the side with the cranks in line with the seat tube, cranks at 3 and 9, and then with your hands on the bullhorns and your elbows bent.