Re: 35-40 MPH, Really?
I was also considering a 700c road bike but went off the idea for the wheel strength so i got a kona lava dome for very cheap and ran 1.5" road tyres. You can run a remarkable average speed on it. I run it as a single speed to cut down on drag, problem is i live in a very hilly area so the gear I chose is just good enough to get me up the steepest hills but this means you can pedal no more than about 25mph on the flat. Downhill i think im freewheeling at around 35mph. I use an 18" frame as I need to move around as you mentioned.