Even with the Zune vs. iPod Sizemodo, it still didn't sink in to us how similar in width the Zune was to the iPod. Maybe we're just idiots. In any case, you can imagine our surprise when we realized we didn't have to buy all new cupholder/music docks for our Zunes.
As you can see, the Belkin TuneDok for the iPod works just fine for the Zune. Suction cup holds nicely even on the rubberized plastic finish, and the iPod connector hole is big enough for the Brown Ninja—that's our Zune's name.
Product Page [Belkin]