Papercraft X is not really one person that has a model that you can customize, but this site collects all papercraft models that can be customized.
All big name can be found over there (Shin Tanaka, Matt Hawkins, me 😉 , ….), but also some smaller/unknown designers can be found there.
We’re aiming to catalogue all of the urban toys in the world!
This site is maintain by Jun aka SonicScape Jun who also has models which you can customize
Jun is also a member of Nice Paper Toys