I was at Sam's Club last night and found this super cool book for Isaac called "The boys Doodle Book." They have other versions as well--one for girls and one that is generic for everyone.
The book is filled with the beginnings of drawings which are to be completed by the child however they choose.
He was super excited about it and started drawing in it right away. The only down side is that it is hard to keep open while drawing in it because it is such a thick book. So, I think we will take it to Office Depot and have it spiral bound for him.