Should freelancers have agents?

This came up on the remote freelancing hacker thread but it's a good question raised by ajpatel.

Well-known actors are in demand therefore it's in their interest to employ an agent to seek out the best work possible and the best rates and to maintain a steady workflow.

Well-known freelancers are in the same position - they can now pick and choose the projects they work on and managing their own workflow is kind of a hassle. Recruitment agents exist for the good of hiring companies - but surely it would make sense for the freelancer to have their own agent who would take a small cut of earnings and place the freelancer with the best gigs possible.

Does any know if any such entity exists and if not surely it's a prime idea for a startup!