I recently finished knitting the Pembroke Vest. I made some changes. I knit it with the 2 year old size for the width, but the 4 year old size for the length (my son is very skinny for his height). I also changed the middle cable pattern to the one from THIS PATTERN. Both of those are free patterns, if you are interested in knitting them.
It was a lot of work, but worth it. My son loves it, and wore it to church the day after I finished it.