Just curious, whats the most anyone ever had/possible to get

Finished the place pedestal quest for the Blackshire gent and found many good things in chest including Mordred.
Still to do the Freehaven quest so will have at least 2.
My sorcerer is besides herself and the druid is jealous.
Speaking of duplicates , any of the other artifact weapons do the same/

Cheers

You may be able to infinitely duplicate most of the quest items. Mordred might be one, and I know that Blackburn's shield can be duplicated. Get the item, go to the Seer, drop the item just outside the Seer's hut and then ask him to find it for you. Step outside, drop it, go back in. Rinse and repeat.

More standard play: you probably will cap at 2 copies for quest artifacts, and 1 for non quest artifacts. I believe the game keeps track of which ones have been doled out, so if you randomly get one of the quest artifacts, you can still find it at the location where it is always set.