From the tie she was wearing, it looked like the POA-style scarf was the way to go. The Charmed Knits book said to knit it flat in a 1x1 rib. I did start out that way but I just didn't like the way it looked. So I adjusted it to the tube stockinette scarf like the Gryffindor one that I made. Much better! I wasn't too keen on the thin stripes - changing the yarn colors (even wrapping the yarn instead of cutting it) that frequently was just not a lot of fun. But I watched several TV shows and listened to a couple of audiobooks and the scarf is finished! I'll be mailing it off tomorrow (it's a surprise!), and hope that it works with her costume. (ETA: The scarf arrived and she is very happy to have it!)
Details:
Yarn used: Cascade 220 Superwash in Blue (#813) and Grey (#816)
Needles: Size 8 circular (16")
Pattern: from Charmed Knits