I do think the comparison between naked women's nipples and Scripture tattoos as worn by many Godly believers isn't realistic. I can see that trying to make such a comparison can cause the argument to seem evocative, but I don't think it's a fair comparison, and I'm guessing that a lot of Christians would think similarly.The flesh is always a problem for those who have not yet overcome it. The pictures you displayed on this thread with tatoos would be offensive to some... so then what?
"Abstain from all appearance of evil." I Thess 5:22
If we need to cover up the flesh, wherein is the witness of which you speak? Should a woman bare her breasts in public because she has a good verse inscribed on them? That may be extreme, but is it, really? How many men would seriously be reading the verses to hear from God?