Today I found a solid way to start my project. An Apple enthusiast named Mike Willegal is selling components to make your own Apple I. He can provide absolutely everything: components (even rare vintage integrated circuits), programmed PROMS etc... He has even produced a set of ready-to-use printed boards that he designed himself.
This is a replica of the original Apple I printed board. Furthermore, even if the components are not all "vintage", they do have a vintage "style", especially with the three blue chemical SPRAGUE capacitors. They'll allow me to create a cool, stylish replica of the original Apple I, see below:
Mike Willegal calls his Apple I replica MIMEO. I like it because it's really close to the original. Compare the MIMEO replica to the hi-res scan of the original Apple I Ad:
Some integrated circuits like the 1x4K rams MOSTEK MK4096 are very hard to find. These elements are essential in order to create your own Apple I. Without them the computer cannot be realized. I'm going to contact Mike to see if all those components are available.
Site of Mike Willegal: http://www.willegal.net/blog/
Mike Willegal's "Mimeo 1 Kit": http://www.willegal.net/appleii/apple1-kit.htm