You for the most part have answered reasonably, therefore what was your purpose in leaving out the most important part of my statement, namely
(actually the odds are much worse, but you figure them out, and be careful, random things have no direction)
Now, given that your coin flipping sequence has occurred, and not being privy to the execution of that sequence, what does the result allow you to say about how that sequence was achieved?
As to your X2000 figure, I mostly agree, however does a 1999 gene difference count? How about a 1998 or 1997 or 1996 or 1995, when does the sequence become chimp/human?
Lets be incredibly generous and say half-chimp. 1/x^1000 is still unbelievably remote. Remember we know x is MUCH greater than 2 (50% chance of the mutation occuring). Yet even 2^64 is so remote as to be impossible for all practical purposes.
Natural selection is extremely powerful.