Sinister Scimitar

Sinister Scimitar is an one-hand sword.

Source
This item is sold in limited supply (1) by  in Tranquillien in Ghostlands. The respawn time on them is random, though they usually reappear every few hours.

It was believed Sinister Scimitar shared a vendor spot with and that if one was for sale, the other would not spawn, however both have been seen at the same time as recently as August 17, 2008.