Thanks for your kind words
Actually, what you describe is exactly what I'm currently trying to do. And, you're right there, it definitely is a bit more difficult to create the grass MDLs... to have them shaped properly, I usually create a bunch of blocks where I want the grass to be, paste them, delete them, create a new level and insert the blocks, then save the whole thingy and open it in MED to insert grass models along the blocks's shape.

As for your question: No, I didn't try it with bushes and trees yet, but will do in the near future. I don't think this could be used for trees though, as a tree has a far too complex shape - but with bushes this should work quite well.