B0SSzombie wrote: »It's much easier to just steal them.
Go to the Abtiquarian's circle in Solitude, and starting from the front door, check every desk, wardrobe, container, etc., until you get upstairs, where the one NPC is standing between the six desks.
That's how I got the bulk of my Solitude Furnishings.
Although from the sound of it, you want Purple Quality plans, which are going to be crazy rare and cost a fortune, at least until a Solitude Plan Container gets added to Rolis Hlaalu's wares.