At what point does the cost become more about the decoration than the writing?

It's diverting to idly look at expensive fountain pens and imagine having one, but if you look closely there's a point after which the pricing is more about the materials, and especially the craftsman ship of the decoration and finish of the body, rather than the nib or writing experience. Where do you see the upper limit where the balance falls into looks rather than writing quality - I'm thinking, for example the Pelikan M1000 on one side, and the Pelikan Toledo or those gorgeous Urushi or Maki-e pens as example of the decorative types. Which pens are on the writing side are at the top end - I'm thinking Montblanc 149, Homo sapiens, King of Pens, M1000 - what else is there?