Hey bud, came across this thread when looking for some other info and just wanted to note for you, that as of yet, I've not found any evidence that the NF-A15 fans can be disassembled for dyeing or painting like earlier 140mm Noctua fans could be. Just in case somebody else comes along and sees that comment they won't get a big fat letdown when they discover the fan blades don't separate from the frame and bearing assembly like most fans do.
At least, not from what I can gather and I don't dare try to apply any more force than I already have, so I'm assuming the general information I've found concerning newer Noctua fans not being able to be disassembled applies to these as well. Sorry for the necro, but I felt it needed to be added.