Many of the bottom up patterns I have run across are cast onto stitch holders then, after joining the work, cast on to circular needles to finish. That way you can pick up any pattern for the stitches to match the cuffs and waist band.
It looks as if you could 'cast off' in pattern onto stitch holders and still maintain the curve of the neckline.
I'd have to play with it to be sure.
Knit 2, Purl 2, Knit 2, Purl 2, Knit 3......Darn!