Hello
I added a post here about making grass with simple cones in XSI, but now I tried it out with hair, and the result is much better, not to mention faster!
Here are some images with slightly different lighting:
I simply added hair to a plane, changed some parameters to make it curl and bend the way grass does, I also changed the shader color to green and faded down the specularity a bit.
Maybe I should write a tutorial about how to do this more in detail? Let me know if there is any public interest in this.