There is a lot of information about paper models and where you can download it, but no/little information about the creative process of papertoys.
How to design a papertoy starting from scratch. How to start with creating papertoys.
Matthijs C. Kamstra aka [mck] wrote an interesting article regarding this subject:
How to create your own Papercraft
Now he wrote about the creative process of designing a papertoy:
Papertoy design – the basics
and it starts from the beginning: a cube and how to make a cube into a papertoy.
It seems that people need some help in the creative process.