Unfortunately, there aren't too many published pics of the YF-23 areound these days. You could always try contacting Northrup/Grummans Public relations office or Dryden's Public Affairs Office (Might be listed as PAO)
The only logos that I know were at my first link here
http://www.af.mil/photos/art_shields.shtml The nice thing about the one featured there is it's in eps format, just no color. To get the color info, you can check out one of those other links. I can't rememebr which, but it has a good shot of the logo on the tail.
That has the ACC one, but no Systems Command. I haven't seen that one around for quite a while. Sorry on that one.
But try going to the AF link and follow the contact us link. Explain what's going on and maybe they'll be a tech sgt at the other end who can help.
Sorry it isn't exactly what you need, but it's all I have.