You can always knit your own button bands in, even if the pattern doesn't show them that way.
As for knitting a larger size, it depends - if your gauge with the worsted divided into the stitches given for the larger size will make the finished measurement you want, yes, that works. If the pattern is a top down raglan, you can increase until the back sts are half the measurement you need.
You can also use a pattern generator where you put in your gauge and the finished measurement and it makes a pattern for you. There's one at www.knittingfool.com and the Incredible Custom fit pattern. For a V neck, just allow only one stitch for each front, and inc at that edge either every other row or every 4 rows, depending on how deep a V you want. Every 4 rows makes a V that ends a couple inches above the underarm.