I think you just have the wrong cross bike for commuting. My Redline has S-bend rear stays for compliance and a 27.2 seatpost with a carbon wrap to reduce buzz. I also have Planet Bike strap on fenders that cover 34C knobbies with no trouble. Finally, my current 32C road tires feel faster than the 25C tires they replaced, which has some science behind it since larger section tires have less rolling resistance and ride smoother. This is why the pro roadies have switched to 25C tires from 22 or 23C.