Don't worry, it's not a post for children's clothes. Wouldn't that be creepy?
|image: Victoria's Secret|
This is an easy shirt to make from an existing long sleeved shirt of your own.
Cut off the sleeves (leaving about a half- inch to hem and turn under so you don't have fraying armpits). Stitch in place.
Cut the sleeves into strips about 4 inches wide. These will form your sleeve ruffles.
Or little ones to fit under a blazer:
(Notice how the ruffles stop just before the underarm. Ruffles under the arm wouldn't be too comfy methinks).