Everyone has heard of Threadless - but were you aware that Threadless has been partnering up with various well-known retail brands (such as Havaianas to crowd-source out the design for other products as well?
I found this infographic a few days ago and imagine that other companies will be following suit (if they aren't already):
Some companies I can think of right off the bat I'd like to see embrace this idea:
Nalgene or Sigg (water bottles)
Chrome/Timbuktu (bag companies)
North Face (or some other winter jacket company)
and any company that makes iPhone cases. Most of the designs are always horrendous.