I used fabric from a regular pajama top. For the doll top, I used the free Pixie Faire t-shirt pattern for Kidz dolls. I lengthened the short sleeves included in the pattern. I also added ribbing to the end.
I used another Pixie Faire pattern (the basic pants pattern) for the pj bottoms. I altered the pattern to be leggings for an American Girl Doll, then I changed that alteration to fit my Kidz doll.