Have you considered "dipping" or using rubberized spray coating? The popular brand is Plasti Dip, but I think there are other options now. My apologies if you already rejected this option, but figured maybe someone out there hasn't seen it.
What's great about dipping is you can just try it out yourself to see how a color looks using a rattle-can spray, then remove it if you don't like it. It peels off like rubber. Sort of a poor-man's vinyl coating, but rubberized. You can dip your logos too, maybe you've seen cars around with blacked-out logos?
I'm using it to black out the silver parts of my car, and the plasti dip is still lasting for hmm like 6 years now? I'm going to try dipping a black rubber liner around my rear windows, because that one rubber part seems to whiten on its surface, unlike the other rubber window parts that haven't seemed to change color over the years. Currently I haven't tried dipping on top of factory rubber, but I have done it on the painted surfaces, the chrome, and plastic.
There is even a guy who professionally dips cars:
DipYourCar - World Famous Peelable Auto Paint