Re: The hardware underneath
And by "roll it completely on your own", you mean "running your own software, on your own operating system, your own hardware, with chips designed, fabricated and soldered into place by you personally."
Anything less is just posing.
Ideally you should also be laying the fibre and installing connectors too, but that would be unreasonable. So long as there's no silicon within your server centre that's provided or manufactured by anyone else, that's probably good enough.
Assuming you're perfect, of course.