I've done some digging on the forums and found that Arthmoor has done a fantastic job at getting the distant tree models to be usable at all. The poly counts have been optimized to the bare minimum. What I'd like to know is whether it's possible to create billboard textures for these trees, and have the game render each distant tree as a simple billboard texture, rather than a complex 3D shape, just like the SpeedTree system works for the other trees in Oblivion.
Is there a reason this hasn't been done yet? I'd love to help create these billboards if it's possible. But perhaps the game engine just doesn't allow billboards for anything other than SpeedTree resources?
If it isn't possible, then I'll still be happy with http://i216.photobucket.com/albums/cc212/darkstorne/Oblivion2011-10-1614-24-45-60.jpg. It would just be great to improve on this already awesome province mod.