Yaknow I didn't even stop to think how that would sound
The company I work at did a million dollar bill - the one you can legally replicate - engraved in several different substrates as a promo trinket with our contact info on it.
It was the most detailed engraving I have had to do - so its the one I come back to for comparision.
And $20's are too obvious anyways. My favorite to date was the jeweler who minted his own casino coins. They ended up catching him when they wound up with more coins at count than they started with. Considering the number made to replace the ones carried out of the casino as trinkets plus the surplus.. thats one busy guy.