Stevie G - I like the look of your game (if it is a game) but I'd definitely scrap those soft shadows. They ruin the whole feel of the place. Why not try a tesselated mesh for each non-static object then line pick the ground underneath for deformation - and just use alpha - that way you can keep the hard crisp edges throughout the game world. It would look just perfect - trust me. You can make different vague shadow meshes to suit each vehicle.
Your kidding right!! Not much overhead in doing at least 4 long linepicks for over 50 moving objects. Not to mention the fact that the shadow would not hug the landscape nicely at all. I'd also have to transform these linepicks based on the best fit for the objects pitch / yaw and roll rotations which is a pain. The whole idea would be dog slow - trust me.
Now, I can assure you that I have tried various other methods and none come close to the speed and versatility of my current method - sure they are low res but so are the static shadows.
Don't get me wrong I'm open to suggestions but not silly ones like that. If anyone doesn't like them then they can turn them off.
Are these better?