Little moon, little moon,
I used 2 images I found on a Google Image search for "cloud coloring page" and "crescent moon coloring page" as my basis for the shapes. The cloud is from here and the moon from here. I copied them into Microsoft Publisher and then adjusted the sizes to the dimensions I wanted. The clouds are about 8 inches wide and the moon fits just under the tallest "bump". This wound up cutting really nicely from a craft felt sheet as there was very little waste on the sides.
Another great cloud flannelboard I posted previously is It Looked Like Spilt Milk by Charles G. Shaw. This book is a wonderful, wonderful storytime gem and if you don't know it, you are missing out!