You may use this as a plugin, if you like the changes to the landscape or else just take the new meshes and make something of your own. I have just started yesterday, but I plan to release the first resource in about 2-3 weeks.
Some screenies showcasing an exterior cave, which can be placed in a large hole in the ground in CS, so that you can enter it through gaps from the surface. I have textured it with small size vanilla textures linking to the environment where I have placed it, you may retexture it with some high resolution ones as you like lateron:
http://img31.imageshack.us/img31/3271/29325696.jpg
http://img31.imageshack.us/img31/2734/99054051.jpg
http://img34.imageshack.us/img34/5466/56182937.jpg
http://img18.imageshack.us/img18/213/30008396.jpg
http://img34.imageshack.us/img34/4646/71599766.jpg
TheDaywalker :rock: