My oldest daughter was asking for some winter PJs, on a limb I made her a nightgown out of some cute winter penguin pattern. I used this pattern and I do have to admit it turned out darling on her. And at 9 years old she 'actually' wears it.
The only thing I did different is I used the same flannel fabric ( I had a TON) and lined it on the inside just to make it more snugly and warm.
I also used some extra fabric and made her an eye mask with it. Even filled it with rice so she can microwave it as a nice relaxing, and 'big girl' addition to her new PJ set.