I love this topic because I passionately believe cycling can be mainstream, and that people can bicycle for transportation and dress normally. When we did the Two Mile Challenge, one of the participants had a goal of figuring out how to dress the way she likes to, and still bicycle. She likes to wear short dressy skirts. There's several fairly simple solutions-- wear shorts under the skirt, take off the shorts after arriving at work. (Hers was a short commute. She could easily walk it--even easier if she would carry the heels she likes to wear.) Bring a change of clothes. Etc.

She ended up not really coming up with a solution during the month we did it, but she admitted that was more lack of effort on her part, that there had been several good suggestions.