I've seen some somewhere too, but they were probably on either the sheet mentioned by Geo, or included on other decal sheets.
It's not too difficult to hand-paint the pennant if you can't find decals.
At work right now Terry so I don't have time to check but I believe the sheet also had Prototype markings; Eagle Strike or Xtradecals seems to ring a bell with me
Had a quick look at Hannant's and Fantasy Print Shop etc, but nothing found.
I feel sure there are some included in some sheets, but they'll be for a specific subject. I think I might have a couple somewhere, but which sheet they're on, and what rank, Lord knows !