OpenUru [1] has the source code and the content creation tools required to do something like you are describing. You might have to modify the client, to handle

OpenUru [1] has the source code and the content creation tools required to do something like you are describing. You might have to modify the client, to handle the perspective change, but it would even allow for online multiplayer puzzle solving and user created content. [1] http://openuru.org/ http://openuru.org/