Think most new upmarket cars ordered these days are bespoke given the option choices, but you do have to manage expectations and have a tolerance for niggles.
Porsche have offered PTS (paint to sample) for as long as I can remember. In early days it seemed limited to very high end customers (the Sultan of Brunei being one that I can recall) but as they moved to the 997, more common. However, with that said, even with the 997 I remember having to submit a request for the PTS colour I wanted and if they had not previously produced it, there was a charge to test the colour on the various materials used on the bodywork prior to agreeing to it. After that, as I am sure you are aware, they charged an not insignificant premium for the approved PTS option. With the 991 and 992, the pre approval seems to have been done away with and the colour back catalogue is open. I'm not sure how they'd react to a regular customer asking for a non-Porsche colour and that would be an interesting test.
With all of that said, paint is just one element. Afaik, Morgan will paint you car any colour, use any leather you want, and, as we know from various owners, are more than willing to do their best to accommodate special requests; this is what I meant by bespoke. I know Ferrari and various other high end companies do genuine bespoke at stratospheric price points but does any other car company do it at Plus Four level? I don't believe so but perhaps I'm wrong.
