Sequencing the Code

The Na'vi are not very different from humans, anatomically speaking.  Here's an outline of what would have to be changed in the human genome to yield a Na'vi genome:

• Eyes; the difference is only in the eye colour.  The code for eye colour could be isolated and replaced with the desired colour (gold-yellow).  
• Nose; the difference is in the shaping of the cartilage and bone.  The top is wider than the bottom, if only slightly.  The structure is flattened.  This code could be taken from a cat and modified in size on a genetic level.  Perhaps a lioness would be the closest thing.  It should be noted that the code required for hair production on the nose would have to be truncated.  
• Ears; the difference is in the position, shape, and ability to move.  The closest thing to this is the lemur's ears, but these would have to be genetically modified in size to be compatible with the Na'vi body.  Also, the code required for hair production would have to be removed.  
• Teeth; the difference is only that the top cuspids and laterals are elongated.  This can be accomplished by cosmetic dentistry.  
• Height; this would have to be manually modified by a geneticist hired by us.  
• Skin; the gene for melanin production would have to be manually modified to be blue.  Pigmentation would have to be altered to produce a Na'vi pattern.  This would have to be the responsibility of a molecular biologist and a geneticist.  

It must also be noted that the Na'vi code must have the information required for the development of the part of the brain responsible for conscious thought (the neocortex) would have to be replaced with code to produce a space filled with cerebrospinal fluid.  This destroys possible ethical qualms.  If there is no consciousness to begin with, then it is not unethical to place a new consciousness within the body.  

Developing the Na'vi Body

Once the genome is completed, the body has to actually be created.  This would have to be done by a surrogate mother, though the Na'vi fetus would have to be removed a month or two premature to avoid internal damage to the mother.  The fetus would simply become too big to fit inside a human womb.  However, removal of the fetus prematurely is relatively safe, in a controlled environment.  The fetus would be allowed to grow in a coma-like state (since there would be no consciousness yet) for a while until it reached a decent size (say, eight feet, though it would continue to grow until a height of about three meters was reached).  Upon the complete development of the skull (which should not take more than a few years at most, or a few months at least), the transfer of the conscious neurosurgically could be completed.