The latest Lady of the Legion is one of those Legionnaires whose code name is actually her real name, the illusion-casting Princess Projectra of Orando:
Projectra - or "Jeckie" as she's often called - hails from a world that is far behind the technological level of most worlds in the 30th Century, being roughly comparable to Medieval Earth. Orando, however, has the advantage of a working system of magic.
Projectra left the Legion to assume leadership of Orando as Queen Projectra. However, after her husband - fellow Legionnaire Karate Kid - was killed, she eventually returned, with some new abilities in addition to her ability to cast convincing illusions as the mysterious Sensor Girl.
This picture was a bitch and a half, and I don't think I managed to convey the concept that I was going for - that her costume is an illusion, which she's in the process of projecting - but there comes a point when you just say "good enough."