I will be getting two tattoos in the coming year, most likely - one on my upper back between my shoulderblades (yes, I have shoulderblades, now!!) and one where the "tramp stamp" goes. The upper back one is in design stages right now - I need to perfect it before next month. The lower back one will be once I either hit goal or once my body decides it's done losing. I imagine neither of these places will experience shift.
However, I would also like to see something on my hip - but I carry a LOT of weight there and I'm not willing to play with that area until I'm done losing. Same with my chest. Essentially, despite others' testimonies, I would recommend that you look at the areas that you PERSONALLY retain fat and avoid those places for tattoos. I could get a tricep tat today that won't barely change by the time I get home. A person I know could do the same and because she carries so much weight in her arms, she can almost certainly count on batwings dragging that tat far out of place.