This isn't every jazz bandleader and composer, but it is a profile of a very serious and active one. The individual, who will remain anonymous, was recently profiled in a detailed case study about different types of musicians by the Future of Music Coalition. This exhaustive breakdown lists every source of income and every expense between the years of 2006 and 2011. The only thing it lacks is hard dollar figures, based on privacy agreements.
Take a look. An embedded PDF is below, and for greater clarity, the full document can be accessed here.