Argh! Double post.

Doesn't Hjerim in Windhelm have the most storage space? You also don't need to do the entire Stormcloak questline, you only need to do up to

Not by much. Vlindrel Hall in Markarth only has a couple fewer containers, and is even easier to get.

Hjerim has a lot of mannequins and storage racks, however. It has two floors, both of them the size of the whole house in Markarth. A lot of that is empty space but that is also nice when you're bumbling around your follower.

Yeah, those things get weird. I had some hovering 4 feet off the floor, others slightly shift this or that way from where they were last time. Other times they turn invisible but can still be accessed. Seems like they have to re-equip everything every time you enter the cell.
Why can't they just stand still, never move/shift, and always display everything? I don't know. Morrowind mods could do it.

~

On another note, I'd use Markarth except I hate that city, and their merchants aren't very impressive. Plus, I have multiple 360 games where the Markarth smith is bugged, and you can't invest any money in her. Yay!
I just do the stupid slog to Dragonsreach to use his, and try to ignore his annoying banter.

Honestly, I could give a rat's underpants about crafting stations in my house. Theres an abundance of forges and labs EVERYWHERE. I used to craft a lot (the I took an arrow in the knee), and not once did I need container or storages while doing that. Get a companion to hold excess stuff, or just friggin drop it. Nobody is gonna take it anyway. I used to let a lot of junk laying around Farengar's area and nothing happened to it.

But then you took an arrow to the knee...

My very first playthrough I started dropping junk on the floor of Breezehome because I couldn't afford upgrades yet. A friggin guard walks right inside and tells me that I shouldn't be dropping my stuff, or someone might take it.

If you have a character who's a dedicated alchemist or enchanter, it helps to have everything in one place. What I do is unload all my ingredients on every trip home into one particular chest, and every once in a while take them all into my inventory and do a big potion cooking session. OMMV.

its an OCD thing, i like my stuff to be neatly stored away in containers and my crafting tables right next them.