I think you can also make grass wave by animating the texture that governs the orientation or the "gravity" setting of the grass. In fact, it occurs to me that you might be able to use Carrara's procedural water textures to get good fluid-like results, which might simulate currents of air nicely. You can find loads of architectural textures all over the Web, by the way. Just Google "architecture 3d textures free" and you'll find loads of good stuff. By the way, your work lends credence to my theory that everything's better when you add a dog to it.