3D printing

Have you ever heard about 3D printing? Yes, it is possible!
3D printing is not so impossible: an open-source project called RepRap was created about 4 years, in 2007.

By the way, you can also find a lot of companies - such as HP - which sell 3D printers.
"The main differences are found in the way layers are built to create parts. Some methods use melting or softening material to produce the layers, e.g. selective laser sintering (SLS) and fused deposition modeling (FDM), while others lay liquid materials that are cured with different technologies. In the case of lamination systems, thin layers are cut to shape and joined together."

The prices of these printers are still high, but they will lower, then you could buy one of them and print a ball.