As a small concession, I decided I'd at least start in the opposite direction. Perhaps we can say hello along the way. I noticed some interesting commentary in Paul's diary regarding genetic engineering. This is certainly a valid concern, and experimental tweakers should always keep that in mind. However, I believe evolution is not, by definition, perfect.
Evolution has blind spots.
Perhaps divergent paths is a better description. Certain paths, once embarked upon by evoloution within a particular species branch, will likely not switch to a new branch after a certain degree of complexity has evolved. A great example of this is the retina. Mammals have blind spots over the optic nerve since the nerve bundle distributes on the inner surface of the retina. Squid, on the other hand, have no blind spot since their optic nerve splays on the outer surface of the orb, achieving full coverage over that portion of the retina.