http://blendermarket.com/products/tesselator

Tesselator is a remeshing addon that helps you create regular quad and triangle meshes easily out of sculpts.

It can create pure quads, pure triangles and quad-dominant meshes with high control over the flow.

Although it’s not exact, it performs pretty well for simple models and can create good looking topology.

The addon simulate a particle system that can be guided by grease pencil and form a quad and triangle complex for the final mesh