Carving a doll cake

Hello all.. This is my first query out here on cakes decor. I have a princess doll cake order for the coming week and have been looking around for a tutorial on how to carve the skirt/gown of the doll with cake. I do not want to go and buy a ball shaped pan since I am not really fond of the idea(However if i cant get the caring right i may just buy the pan) I have seen a lot of tutorials on carving a ball shaped cake but it looks very unnatural when the decoration is done since it looks like a doll sitting on a ball.. I am really interested in getting a shape like the image below. Please guide me on how to carve this shape out. If there are any tutes out there please do post a link for me to check out. Thank you all.