I finished a sweater last year which looks great except the sleeves are too long. Is is possible to unpick the side seam a bit, unravel some of the sleeve, and then re-knit the rib cuff in the opposite direction?
Yes, you can do this. I've done the very same thing. You can't just "ravel up" the sleeve from the cast on but you can cut and then reknit the cuff.