Is there anyone around that still pantographs parts?
In the U.S. this is normally called engraving and there are LOTS of engravers out there. I subcontract out crowns and bottom brackets to be engraved with my logo's. The engravings are filled with contrasting colors after the frames and forks are painted
Is it difficult to do?
Not if you have an engraving machine (like Hermes), are willing to build the tooling to hold the parts you want to engrave, and have the necessary experience using the engraver.
The current alternative to conventional (old fashioned) engraving is laser engraving of anodized parts and many consumer products have parts that are laser engraved.