I have noticed quite a few hatbands around this year and I had the idea to build a hat on a hatband. My favourite hat I ever knit was this type. I made it when I was in university (decades ago) and I loved it. It fit better than any other hat I have ever owned since. I got the pattern from a random magazine like Canadian Living or something. I owned the hat for a couple of years and then lost it. I tried for years to find the pattern again but never did.
I have not managed to recreate it by a long shot here, but this is a start. What I did here is start with a tube. I cast on 39 stitches and knit them with my 9″ circular sock/mitten needle. I think I will reduce this to about 35 next time because I think I can still use that needle (I have a hate on for sets of four…all that needle changing drives me spare) but the band won’t be quite as wide, which I think will work a bit better visually. I continued on these stitches until just before it was long enough to go round my head then I did a slip 1 knit 2 together pass slip stitch over around and knit a couple of rounds on the 13 stitches and cast off. I then picked up from the cast on edge and did the decrease, knit a couple of rounds, cast off and sewed the two cast off edges together.
After I had the band finished, I used straight needles and cast on 10 stitches. I purled outer two stitches on each side of a 6 stitch cable which I did long enough to go round the center of the band. I used a circular needle to pick up 98 stitches around the band about 3/4 of an inch down and then picked up the stitches from the straight needles as well as the corresponding cast on stitches so that the cable went around the center of the hat band. I added 8 more cables around the hat (purl 6 cable 6 around) and finished body of the hat normally.