from an item w/o the "can't be dropped" check box? Example, the Elder Scroll. There's no obvious "switch" as there was in Ob or even for the other more mundane items in Skyrim. Is it's quest item status scripted into it? I'm seeking to make a mod for myself similar to one for Ob that removes quest status, but that seems to be undoable.

If it's glued to the player, odds are it's filling a quest alias with its "Quest Object" flag ticked.