ADU rectangles and other textures

Hello.

I am trying to create a page similar to GT3 / motec dash layout, and they have rectangles with rouded corners, how to atchieve this ?

My first thought was to create a texture like so and upload it, but it is not adjustable, and logicly i will try to avoid creating 10 diffrent textures for each field that I would like to display.
Similar to what this guy did. https://www.youtube.com/watch?v=PbrO28yuOOQ