A few good cnc metal prototype images I found:
Floor Panel Prototype
Image by Caliper Studio
Caliper Studio created a stainless steel cast glass lens floor method for the lobby of the Metropol in Williamsburg Brooklyn. Its design and style borrows tips and strategies from the front facade of the Cassandra cinema also made by Caliper Studio. Each cast glass lens is sandwiched amongst steel bottom and stainless steel prime bent panels. The steel bars supply additional spanning capability, even though the wood strips connect prime and bottom panels to ensure that they act as a single unit.
Caliper Studio, 2009
Image by UCL Mathematical and Physical Sciences
Prototype for the ExoMars Pan Cam: this image shows the optical bench, the primary metal structure that will hold all the optical elements, getting machined in a CNC lathe
(Post from rapid prototyping companies in china blog)