Are there "brand name" metal roofing manufacturers?

Yes.  Your installer should be able to to show you a full range of colors and custom options that are available.  This is something that is readily available from all of the top level metal roofing manufacturers.  If your choices are limited, it probably indicates that the installer is using an off-brand product.  Ask for manufacturer literature.  Your installer will be glad that you asked - he chose the product for specific reasons and he wants to share them with you.  Also check out the warranty.  All established manufacturers fully back their products for 30 or more years.  If you Google the term "metal roof" the industry's top manufacturers will show up on the first few pages.