I produced a little Star Trek parody in sixth grade, and I can sympathize with how difficult it can be to find matching costumes on short notice. The guy playing Chekov ended up with a yellow short sleeve 1st season TNG uniform variant that was worn by female officers. Fortunately for him, only us Star Trek nerds recognized it for what it was.
Mine was better then this, although it suffered a bit when I cut Scotty's scene just because I really hated that kid.