My wife came to me and asked me to make a "bookcase shaped like a tree." When i asked her to elaborate, she drew me a sketch of a tree, and said "I want the bookcase to look just like this." After several weeks of thinking, drawing, cutting, and painting, I installed her (the first) Tree shaped Bookshelf exactly as she had drawn it. (look at the sketch photo)
This led to several other fun shaped bookshelves, one of which is an AT-AT for a 1 year old's nursery (he's got cool parents) that had been featured on MindHut and SheKnows.
I use the same material custom cabinet makers use for their drawers. Its called Baltic Birch plywood. Unless your building a boat, there is no finer material plywood. Its completely solid (unlike cheap plywood which has voids, and pockets). Put simply, if there were stronger plywood out there, this last paragraph would be about it, and not Baltic Birch.
We had our first bookshelf installed in our living room. Talk about a conversation piece. It was right in front of the front door, and everyone who came in the house got to see it, and no one failed to comment on it (they all told us it was awesome.)
Clients have told me that they chose the Tree because it was less themed, and really was shaped by its decorations.
If you look between the two pictured, you'll see that this design was reversed.
Don't be fooled by the Tree. It was our first design, but nearly any shape is possible. We've been asked for Tractors, Animals, Piano, Doll-House, Dr. Suess Building, Action figures, you name it.