This one is crochet, but you can kind of see the scale compared to the doll:
http://www.ioffer.com/i/annie-s-atti...ttern-41150031
This is what I remember about Barbie:
http://www.quiltingarts.com/blogs/pi...oll-quilt.aspx
Don't forget to show us what you come up with. It might even be a fun project for your granddaughter to tackle.