Well there are two level 4 ones on Kniles the Flenser's body and a level 5 one if you talk to the Seeker Smith and choose the right dialogue option, but I don't know more than that.
Unique items are not especially relevant in this game given the rapid gear turnover which is required.
Yeah, the scaling is completely broken, honestly. A unique item on one level is most likely completely outdone by a simple magic item on the next. It's quite sad, honestly - you never really get to hold on to anything, and no loot feels special.
