One of the best things I ever made, according to my sister-in-law, was buntings for her twin daughters. Since they are now 24 going on 25, I have no idea how I put them together. All the nieces and nephews want them for their babes in arms, though, so I let Elizabeth talk to me from her book "Knitting Without Tears." Her modular sweater was the perfect pattern to adapt:
(Sorry about the sideways photo!)
I used Woolease from Lion Brand - warm but washable! I don't know if it will actually pan out, but the cream colored bottom is designed to pull out and the bunting converts to a sweater for a 2 - 3 year old. I will probably end up steeking the bottom of the blue, too, if we actually do this.