The Scarred Lands setting did indeed have tattoo magic. It's detailed in both Relics and Rituals I and II, as well as some more in Burok Torn and I think Hornsaw sourcebooks, maybe in the Player's Guide to Wizards, Bards and Sorcerers.
Also, there was a Dragon Magazine sidebar that described a magic tattoo feat. I don't remember the issue, but it was essentially a variant of Brew Potion.