Go give it a go and as a minimum, you'll learn something about why it doesn't already exist yet and in the best case scenario, you'll create something that lots of people find useful!

Have you actively seeked out such an opportunity, or are you waiting for one to present itself?

You would use an engraving service. Almost every town has one[1]. There are also online options[2].

1. https://www.google.com/search?q=brick+engraver+name_of_town&...

2. https://www.etsy.com/market/brick_engraver