One dropped when camping the mobs for the VT frame in near IV. It definately looks like a centi longsword and was sticking up out of the corpse after it had died. Dropped from one of the three mobs behind the spirit thingys.
Was a 7 min timer on the corpse and no one close to loot it so sadly it rooted as I was the only hybrid there and had a better weapon. Was a nice suprise though, we got lots of other droppable loots but I missed on my frame though two others got theirs.