Looks like it is probably still a bit early in development to use for any production work. However, might be worth checking out.
Blurb:
“Synfig is a powerful, industrial-strength vector-based 2D animation software package, designed from the ground-up for producing feature-film quality animation with fewer people and resources. While there are many other programs currently on the market to aid with the efficient production of 2D animation, we are currently unaware of any other software that can do what our software can.”