Been messing with some terrain tools and anded up with this.
Here is a terrain made with GeoControl 2 Demo and the terrain toolkit from the unity recources.
The webplayer is a bit heavy though.
Looks really nice, but I only got about 20 FPS on an ATi Radeon HD 5750. How many polys are there?
Is it me or it’s one of my favorite presets (in GC)? 
Yeah, GC is a great tool, but I don’t really like the way it’s made, so I stick with presets or use another tool. :?
Edit: BTW, I think the terrain height is too high, I’d reduce it by 2.
This is cool, but unusable on my MacPro 8 processor workstation???
Very glitchy and slow frame rate.
I like the idea though.
That’s an understatement.
For anyone on anything less than a Mac Pro 8 core with an nVidia 8800GT, don’t bother. 
It IS neat though.
Is there a button I can press to see what frame rate I get? It has to be high. Using my Dell Precision M6400 this demo is real smooth probably 30+ easily.
Also, Why does my mouse never work in the web browser unity stuff?
Looks great! Runs smooth on my system.
i7 920 OC @ 4ghz.
nvidia 480gtx.
Got 30 easy on my system though the inital download was long. very neat though!
specs:
i7 870 quad @ 2.93Ghz
8 GB RAM
Geforce 480 GTX
Win 7 64-bit Ult
Told you 
The biggest framerate crusher is the pixel error setting on the terrain. It is set to nearly 1 for lush detail without much popping.
Also the heightmap is 2048x2048!
It runs nice on my core I7 but it is safe to say most people on this board have optimized kit for games and are not representative of most computers!
I also made a more light version with geocontrol only 1024x1024 and should run on any system and still looks a lot nicer then making terrain from scratch!
The Webplayer is here
Geocontrol has a terrible interface but the presets are fantastic and VERY realistic!
Still looks great with the reduction got about 63 FPS 