Unless a Scheisskopf is something to be eaten, the proper German would be "Ich bin Scheisskopf." Using "ein" changes the meaning completely.
When JFK stood before the Brandenburg Gate and said, "Ich bin ein Berliner," what he was actually saying in German was "I am a jelly doughnut." To say "I am a Berliner," he should have said "Ich bin Berliner."
Urban legend.
“When JFK stood before the Brandenburg Gate and said, “Ich bin ein Berliner,” what he was actually saying in German was “I am a jelly doughnut.”
Pure nonsense. I spent 4 years in Germany as a translator and the rest of my life refuting this nonsense.
http://urbanlegends.about.com/cs/historical/a/jfk_berliner.htm