Is it possible to generate a complete public address with vanitygen? FAQ says it's possible to use vanitygen to search for a match to a complete address yet when I input a complete address I get an "is too long" error message. Is there a way to run vanitygen using a complete public address?
It's so unlikely to succeed that it is not being offered. One could be tempted to say it's not possible:

Your chances are along the lines of 1 to 2^160. That is 1 to 4.666587*10^172, or very roughly rounded, 1 to 5 followed by 172 zeroes.

To put that in perspective, if you could create a billion addresses per second, the expected time to find a collision would still be longer than the age of the universe.