Vray grass tutorial part 2 « Peter Guthrie. Longer grass - some stats: approx 8000 polys per proxy x 1000 proxies = approx 8 million total polygons. 3dsmax uses about 2 gig memory for this scene and each view rendered pretty quickly considering I had vrayfog and depth of field on.
Note: I use vrayscatter (a commercial plugin but well worth the money) to scatter the proxies. There are lots of tutorials for it here. You can also use scatter by Peter Watje, advanced painter, Forest by Itoosoft, Groundwiz Planter or 3dsmax particles. Vray grass tutorial part 1 « Peter Guthrie. The 3 individual blades of grass were modeled as a plane object with 8x1 segments, collapsed to an editable poly and then I moved the vertices into position in the left and front viewports.
You could use a bend modifier as well, just make sure the final object has as few polygons as you can get away with. I then used a very handy script called advanced painter to 'paint' about 100 blades of grass over a 1m x 1m plane object. Set advanced painter to randomize mode, tell it to scatter as copies (not instances), pick the 3 blades of grass as the objects to be scattered and set the min and max scale and z rotation values to something like 0.75 - 1.25 and -45deg +45deg.