From what I can tell, the width from window to corner is narrow and you won't get close to your rendering in regards to the amount of space. Without width, you will be depending on height, which may be more difficult for your daughter. You can get about the same or more storage and not have to invest in custom made, using a large bookcase - move her desk to under the window and place there. Baskets on the shelves makes it easy to store like items. Slide a storage bin under the bed, or decorative boxes, which look really cute from the side when they are lined up. You can also add an ottoman at the bottom of her bed - great seating for a friend and if it has a lid - more storage and the more hidden, the less busy the room will feel (also easier to manage).

Kids' bedrooms · More Info

I think you could do narrow cabinets on each side of the window for that much need storage and I would have them with doors on the bottom half for sure

The space you have around the window looks more like it would fit something like these shelves. Then just set a bench seat under the window. You could close the bottom with doors, but to save floor space, keep the depth to about 12-15". You could do the same thing all around her bed. There seems to be a lot of wasted wall there.

Bedroom · More Info

I think that you have a good idea. My daughters' room was like this too. We moved into a small house that was built in 1930. No closets! I think that shelving with drawers would be good. If you still think you need cabinets, put cabinets with adjustable shelving on bottom part of shelves and drawers under the window seat. You can never have enough storage!

Also, you do not have to have as deep a space for the window seat as it looks in the idea photo, this will make drawers work better and save on floor space.