You could model a single instance of a hair, or a few hairs and use the particle system’s object visualisation. Yafaray will render that, but obviously it will involve a lot more vertices and therefore more RAM.
EDIT - Actually, there is a way to render hair with Yafaray, but it might be complicated.
Earlier versions of Yafaray integrated with Blender differently. It involved replacing the Yafray code in Blender’s source with Yafaray code. It can still be done, but this method does not work with current versions of Yafaray, so you would have to build the special Blender version and run it with an older Yafaray version. Also, I’m not sure if it will exactly replicate the way hair looks in Blender as the integration is not 100%, so some of Blender’s tools may not be available.
I made this with it a long time ago:-