Jen from Eat. Sleep. MAKE. shares a free pattern for her Sienna top, a bow back t-shirt for little girls. This is SUCH a cute top!! The back of the shirt is scooped low, with two bows stitched across the opening. A small pocket accents the front. Her free pattern makes a size 4T. If you need another size, you could probably adjust a t-shirt pattern that fits your child using her pattern as a shaping guide. Go to Eat. Sleep. MAKE. for the free pattern and tutorial.
[photo from Eat. Sleep. MAKE.]