I don't know if agents would work - they work in movies because you shoot one, then wrap and move on to the next one. An agent can be constantly looking out for new films to work in. Unless you're exclusively seeking short-term contract positions, will you actually communicate with the agent frequently enough to build a relationship? If an agent keeps placing you in companies that either implode or make you want to leave, it doesn't seem appealing to work with them again. If they do place you in a job that you stay at for multiple years, will they be available when you want to move on?