If you need to make a booklet, you need a long reach stapler. These can cost several times more than a standard desk stapler. The office where I work now has one shown here. A few years ago I was working in an office where there was no money for a long reach stapler, but we needed to make booklets.
The long reach stapler shown here is really heavy duty with very strong components. Someone did tape corrugated cardboard pieces to the steel base for stops on different sizes of paper.
Step 1: Choose the Stapler
You need a donor stapler that lends itself to the necessary modifications. A Bostitch-Stanley desk stapler like the one shown here works well. This photo is from Bostitch-Stanley.