This is a world i created using BiomeTerrain minecraft mod this is one of my best ones and for those of you who don't care how i made it and don't want to find out I'll have a link to the empty world for you to explore and create. For those who do care and want to find out more here is a link to the mod http://www.minecraftforum.net/viewtopic.php?f=25&t=136843
Once you have installed it just like all the other mods shouldn't be to hard but post a comment if your having trouble. Once you have installed your settings file in your .minecraft folder can be replaced with mine so it will generate levels similar but different each time.
Link to my settings file www.2shared.com/file/nawFxFM1/BiomeTerrainModSettings.html

Now when your ready to handle some of the community's crazy maps a good site i found for that is here http://www.minecraftforum.net/viewtopic.php?f=25&t=93573
this will give you the settings you simply copy the settings and paste it over all your settings and generate a world.

Additional Notes

World save is just one of the many you can create with this mod I am uploading to because I worked hard on getting the settings to create a world like this and some people don't know how to use the settings or want the world for a server.
Hard map to survive you start off with 128 saplings and you have to plant and grow your own trees
the map is 42 MB big so you should never run out of exploration room and it takes a while and pauses a little on the first time loading but other then that its fine.
some of the caves are breath taking.
I did copy most of the text from my previous world but i did update the links.