Actually one of the elders from my local cong had a few tatts- they look old and faded (from his pre JW years I imagine???), he must have been human before joining!
If it was/is a tattoo you had done before 'knowing or learning' the truth- then no DF! but it was made pretty clear to me during my time as a study that getting a tattoo was 'off limits' for JW's!
Personally I would have to say Fuk them! it's your body mate, do what you like too it... I'm getting my kids names tattooed on my ankle for my birthday this year- I'am getting it done to look like a chain with little elephants inbetween their names, kinda like permanent jewlery- (i orignally wanted 2 dolphins around my belly button but they would have looked like humpback whales after 3 kids LOL).