it's arguable how off-role it is : support-tanky ashe.
Not quite a dedicated build, when I'm left ad carry with no real support (you know those pantheon/volis/mundo). I grab ashe, if I can,t play carry for some reason (like a voli taking all the ks because he hits harder than me), I'll grab gp5/tanky item and let him carry. When teamfights comes I can with some luck harass, snare and survive some burst.
If the game drags on, I,ll eventually transition into ad. But I,ve finished games in 30 min building tanky ashe with gp5.