I suggest that you change the way process improvement personnel are currently managed in the government. Instead of hiring outside contractors, or term employees, make process improvement its own job series and career path. By allowing people to advance in their career along the process improvement path, you will get the most bang for your buck.
Training process improvment experts right now is not cheap, and yet we are wasting money training people that will very rarely do the work for more than a year, if that. By designating a career path for process improvement experts, not only would you save in training costs, you will also reap the benefits of having experts that truly are experts. They will have been around long enough to get the experience needed to do process improvement right.