The New Orleans class USS Kyushu was seen as a wreck in the "Best of Both Worlds" graveyard scene - so far as I know no New Orleans class has ever been seen before or since. The biggest problem in writing a spec for this class was explaining the three very large projections on the hull - two on the saucer and one on the bottom of the engineering hull. There's no canon explanation fo these that I know of; originally I had them pegged as torpedo launchers, but they're a bit on the large side for that, and given the 'frigate' designation of the class this is an awful lot of firepower to tote around! In the end I decided to claim that they're an entire self-contained torpedo system, designed to free up internal volume for more science labs and so on - it seemed a reasonable explanation given Starfleets peaceful ethic.