I think John's post on the modern perl blog is the most rational dissection of this "problem" that is plaguing the perl community.

Few people outside the perl community see "Perl 5" and "Perl 6". For most people referring to the language they simply call it "Perl."

For marketing to developers specifically, I think the biggest hurdle isn't the name but the stigma attached to the language. Most developers I talk to outside of the perl community still see perl as a "write only language" that consists purely of "line noise." They don't specifically say whether they are talking about Perl 5 or Perl 6. To them there is no distinction.