Here is a very, very quick script that generates 3 Alpha brushes. They are very close to the ones I used in the above picture. Use those with the Simplebrush, Flat color material and Freehand Stroke(Space set to 0).
Alpha hairs -1.zip
You need to match the draw size, alpha and pen pressure(if using a tablet) to get what you want.
I used a texture to generate the colors drawn and the Simplebrush slows down considerably when using a large Draw size and a large Alpha. You can set Draw to RGB only and turn off Zadd to speed things up a bit, but that of course means you have to draw on top of an existing material, preferably the Flat color material.
Thanks for the comments