I did this as a Christmas present for my fiance. I used a print to trace the lines onto the black shirt then I did the rest free-handed with an airbrush. He loved it and so has everyone else that saw it.
If you want to see the original that I received permission to paint on this shirt, you can find it here: http://drachenmagier.deviantart.com/art/Bahamut-SIN-110546180