You might have this site booked marked but they are selling real flags on this site:
They seem to go from 90,000 to 900,000. I thought the 3rd Tn's flag captured at Fort Donaldson was very nice. They say its a one of a kind. Its Dark blue with a white disk in the middle (very close to Cleburne's div). The 66th Illinois captured this flag along with the 18th Tn.
Very interesting site, they sell more then just flags.
Good luck on your search!