Carpentry and Woodworking - Advice for building a hanging nook desk?

We put in a staircase in our kitchen recently, and have a half wall around it. On one end of the wall, we were going to have a cabinet. My wife wants me to get my laptop off the dining table, and I was looking at the space and thought I could put a small desk there.

Here is the space:

http://wuld8q.blu.livefilestore.com/y1pxXyBjtnRXRalhBOysTuwFjBsHb2kMJQqLRFEoFDa-QmBIb-JCcp-5K4zL4VCsZv0UgBkKeMkyxuGYriP9RMkPdYKJqik3iu2/IMG_8327.JPG

I am thinking that I could run a board along the wall between the doorway and the half wall, and then another along the half-wall. On top of this, I could a nice piece of plywood. My concern is what to do with the unsupported side? I have kids, and I am sure that the would end up hanging on it. Also, there is a small reducer between the kitchen and dining room floors, so some kind of support on the right side would help keep a chair from rolling off the edge.

Any advice?

Thanks,
~john

I would enclose the right side with an end panel to support the right front corner. Just my 2 cents. Good luck with your project.