I'm one of those people for whom 650c wheels were actually made (4'9")

Are there other short people racing on 650c wheels who have also raced on 700c? I know I can only get into a true aero position with smaller wheels, but I'm currently racing with a 700c (Specialized ruby with clip-ons). I'm thinking of switching to a 650c road bike with clip-ons, or a 650c TT bike. If you have done this, can you let me know the advantages and disadvantages speed, efficiency, and aero-wise?