ComponentSource is a very good place to look for when you are looking for tools and components. If it exists, they have it. They have things in all price ranges, even some freeware, and their price is often lower than going direct to the company that developped the tool. I have dealt with them for many years, and the service is excellent.
Here a result for what they have in 3D charts for .NET: http://www.componentsource.com/relevance/index.html?q=%2Enet+3d+chart