The answer to your main question, if I remember the answer I heard before, is that it's a special application designed exclusively for the Apple Store point of sale systems (Think Secret mentioned the name "Maestro"--not sure if the demo Mac app thing is a small part of that, or a seperate app). If that's correct, you might be able to sneak a copy out of the store and hack around with it, but it's probably not available elsewhere. I could be wrong, though, and there are certainly freeware apps that do something similar if I'm not.
The answer to question 2, if I understand what you're asking, is a piece of shareware called "SharePoints"--it lets you set up all sorts of lower-level permissions and sharing stuff. Either that, or just buy OSX Server--Workgroup Manager is very easy to use and works great.