When I worked at a university I often wished we could bring back the academic robe, because some profs dressed like homeless people. They expected their astounding intellects to communicate all their authority. Actually, it rested the power of the gradebook, but they thought it was their fantastic minds. It would however, have been nice to have a way to distinguish them from the homeless people frequenting the cafeteria. Even then, it wasn't quite right that they wore shorts and tennies to class. What does that say to the students who are paying literally thousands of dollars to sit in your class? Show some respect, dudes, and keep the calf hair under cover until summer semester. Don't get me started on the profs that rode bikes to work and didn't use the shower before class.
Lyn* it sounds like you aren't having any problems 1) relating to your patients in crisis, 2) establishing credentials with peers and opinion leaders, or 3) getting the soul sucked out by trying to fit into a uniform not of your own making. You seem sensitive to all three issues. From what you say, your instincts have guided you just fine so far.
As for striking the right professional note, I think you can risk overdoing it by combining sleeveless, fit & flare, fanciful prints, your height, your age, girlish hairstyles. Some of those you have control over, some you don't. And it is so situation dependent. Is the head of department going to surprise you by sitting in on a consult? Are you going to get thrust in front of the media if some whackamole goes postal on your shift? Can you keep an emergency lab coat nearby if you have to deal with a family member who only responds to symbols? You know the answers and it seems like you are doing just fine navigating these tumultuous waters. Otherwise, let it happen first!