While sorting through clothes to donate I found a bunch of stuff that could pretty easily be converted to little girls clothes...
Maternity shirt into...little girls skirt
This couldn't have been easier, I just chopped it and sewed the casing for the elastic and put the elastic in. I used all the original hems, so this one was minimal work. (maybe 10 minutes)
Maternity shirt into...a little girls shirt
This one took even LESS work, I just took up the side seams and shortened the straps. Instant tunic. (less than 10 minutes)
I did cut out the Motherhood Maternity tag, because frankly, it's a little creepy to have your 7 year old wearing clothes from a maternity store.
Old undershirt into...a little girls t-shirt
Laurel has this t-shirt that she loves (and I like the way it fits), so I laid it down on top of the old shirt and and used it like a pattern. I cut 1/4" around the whole shirt. I used the scraps to make the new neck-hole, then I just sewed the front to the back, hemmed the sleeves and put elastic in the shoulders and bottom hem for some shaping. (I used the original bottom hem of the t-shirt, so I didn't even have to hem it!) (30+ minutes)
I have a one happy girl.
I feel like Maria from The Sound of Music, making play clothes out of curtains...and there is nothing wrong with that.