Instead of Recruiters, do Technical Business Consultant Agents exist? 
While recruiters' customers are typically the hiring organizations,
agents' customers are the consultants.  If they exist, an agent would
be paid on a percentage basis of the consultant's hourly rate
throughout the term of a project.  In turn, the agent would have the
consultant's best interests in mind even while the consultant is on an
assignment, continuing to market the consultant and searching for the
consultant's next "better" project.  "Better" would be defined by the
consultant using parameters such as hourly rate, challenge level,
breaking into new areas, work environment, work locations, etc.

Assuming they are out there, how does one find the best Technical
Business Consultant Agent for them?  Do you have any
recommendations/cautions prior to creating this agent/consultant
relationship?  Please include any resources that might be helpful. 
Thank you.