I've made some more progress in my hopefully-to-one-day-be-released terrain rendering engine(which will be free for non-commercial use). I made a youtube video of my recent advances which include smoother paging for foliage info.
http://www.youtube.com/watch?v=KM4gLfR7bIs
The test program runs at about 43 fps on my GF 7300GT. View range is 1000 tiles. One of these days I'm going to release a small demo. There's another video I released a while ago too that has some occasional bad loading lag that I have since eliminated. It shows a little more of the terrain, and doesn't have animated folliage.
http://www.youtube.com/watch?v=caBll958tqU