I think you might've been led to that by preconception, because it seems to me that the appearance of the body is completely consistent with being a physical object (and that someone unfamiliar with Cortana would likely assume it as such). In particular it's very sharply defined, and reflects lighting just as you'd expect. Of course, one could always posit that it's some kind of super hi-tech hologram which can be like that. But you take my point I hope.

Actually there are also some lighting related effects going on with her head. There's some reflection off the hair, and also the hair casts a shadow on the face. So even if my notion about just her head being holographic were right, that would be some pretty nifty holo-tech!

: but if she had the suit manufactured then the styling can be explained
: away if in every other way the suit appears more physical than
: holographic.

Well, it certainly wouldn't be surprising that the styling of the conjectured physical body would be reminscent of her past appearances.

: I do like the idea though of mobile holographic projection in the shape of an
: advanced/robotic human container/base/form... :)

Also seems a fairly natural thing to do, if the technology is available.