I wonder if I could find something shaped kind of like this in the size for my handlebars? Somehow, that is the inspiration. Edit: I added another.
View attachment 143891
View attachment 143892
As to your question though........thermo forming! Use your bars as the template, add any shape or definition you want, and bada bing, custom formed
You could even mold your numbers in to be 3d if you get the draft angles right on the edges
YMMV