I came across the Ana White site. http://ana-white.com/2010/09/playhouse-loft-bed
She has lots of interesting projects that can be built. I really didn't want her specific look because I wasn't about to cut all the little pieces that she had for the top railing. However, I did like the simplicity of how she joined the sides and I used that joining in my bed.
I already had a vision as to how I wanted the bed to look so I made a lot of modifications. I found an old cabinet at Goodwill that I added and became part of the steps. This also allowed for storage on the bottom.
For the two towers I made simple bookshelves with a little extra trim work. They are screwed in after the bed is together and can be removed. They are open towards the bed with a shelf that allows for space for a clock, books and whatever else kids like to collect.
Part of the fun is personalizing the bed. Have fun with it. Trim it out and paint it to your child's tastes. Paint it grey and white and you can have a totally different look. Add a drawbridge or curtain to the door. Use a slide instead of the stairs.
If anyone makes something send me pictures!