Really? I thought I tried natural dyes with a quarter staff...hmm. I'll have to try again.
Lit torches are one of the few skinny vertical items ingame. You could get a vertical effect dying yarnballs black (or grey) then stacking them up, but at the expense of lockdowns. Another option might be silver coins, two of them will make a thin vertical line so you would not need to stack as many on each other, but because they sit low on the tile they will not go very high. I might mess also around with those little tokuno paintings (as door panels) or clock frames, and do a dyed yarnball for the door knob (if it were me).
