Dear Michael
I know the people at Rhode Island and have bought from them some colored cables with color stripes.
Normally it is relatively easily to source cables with one base color and a combination stripe.
But there are some others with three color stripes that are hard to find.
As you mention this is a hobby/business so the work volume is not overwhelming.
In the future when I get older I may purchase a machine to produce my cable color coding system instead of depending on others.
On the other hand at the moment each project is unique, and that is specially what differentiates my services from other providers. I am frequently asked to perform a lot of customization and retrofiting. Therefore the harnesses can not be produced in anticipation in a serial process.
And finally not everything is damaged in an old 50 year old harness. That is why I reuse, most of the connectors, pins, and of course change the lines I know fail the most, or those which I want to increase its capacity to handle a larger load.
Connectors housing when damaged are replaced for new reproduction ones.
Best regards
L.Peterssen
Www.wiredoktor.com