Since I live in a bit of a chilly area of CA., my guys wear little T's in the morning and evening, sleep in them and every day in the winter unless it's a really cold day when we go somewhere and then they wear jackets.
What I do to get the T's I want is, I buy the ones that snap at the crotch in a 6 month size for both girls, then measure down to where it would come to the groin area and cut the bottom half off then stitch soft elastic to the inside of the shirt about 1" from the bottom. I don't even hem because they don't frey. Simple.
Here are pictures of some of their shirts and Azrael modeling one.
http://i14.photobucket.com/albums/a3...eshirts001.jpg http://i14.photobucket.com/albums/a3...eshirts003.jpg http://i14.photobucket.com/albums/a3...7-11-07001.jpg http://i14.photobucket.com/albums/a3...7-11-07002.jpg http://i14.photobucket.com/albums/a3...7-11-07005.jpg