For your needs, a single speed road bike conversion might be a good option. If you keep an eye on craigslist for a roadbike that is your size and is of your liking you can buy or build a single speed rear wheel and remove derailleurs, extra chainrings, shifters, and switch to a single speed chain. Most older road bikes will have forward facing semi horizontal dropouts that are perfect for singlespeed conversions because they work well with a rear brake and allow chain tensioning. If you have a big budget, by all means keep shopping for singlespeed frames, but if you want to save some money and get a comparable bike, look into converting.