Finally going to make the kids beds... or at least in a few months I am

So I am planning on building loft/captains style beds for the kids. This will be the basic structure (minus the headboard). 

Then I am going to attach espresso stained beadboard on the ends. Then underneath part will still be open for a play area. I'm planning on having them in an L shape in the corner of the room and in between the beds will be a big square box that is about two feet taller than the beds. Again it will be covered in beadboard and the top will have a thick covered cushion. I imagined it will be about 39 inches by 39 inches and it will make a great place to play and read. If there is a way to cut open and archway type hole in each side under the beds I would like to do that so the boys can crawl around through there. However I think that might be beyond my skill set. I still think the kids will have a great time playing and hiding. 

I want to build something similar for the girls (only with white beadboard) however Bella already has a beautiful intricately carved white headboard and a full sized bed. And the girls room isn't shaped right to do the L shaped thing. So I have no idea what I will do.
We have a "spare" room which is really just a large closet inside the girls room. More like a storage closet. It is finished except it doesn't have any vents in there so it can get cold in the winter and hot in the summer. I thought about just setting her bed up in there for the time being but I don't know.
I do like the idea of the mini loft beds for them as well. It's not as fun to not have the reading nook, though maybe I could have one behind each of their beds. Or maybe I'll build a "window seat" with bookcases on either side for of their beds. Though that would delay things quite a while I would imagine.
There is also the possibility of doing a double sized loft and then sticking a smaller mattress below for Maeve.

Anyway, that's going to be my project for the next year or so. I'll make sure to take pictures and update my progress.