Many people are saying that Perl 5 should be renamed. I disagree. Perl is Perl. That's what makes it great. However, I agree that the 5.x version naming is a burden for people who want to advocate the modern relevance of Perl. So, why don't we just drop the "5."?
Perl 12. The current version of Perl is 12.1. That looks right to me. It just fits. Perl 12.x (and 14.x, etc...) just makes more sense because it conveys that Perl is mature (it is) and it has a healthy schedule of stable major releases (it does.)
This idea is not unprecedented.
Is it Solaris 5 or 10?
~> uname -r 5.10
Is it Java 1 or 6?
~> java -version java version "1.6.0_16"
I'm sure that there are other examples of this.
Nothing technical has to change. Perl 12.x will still be Perl 5.12.x when you install it on your system just like Java 6 is Java 1.6 and Solaris 10 is Solaris 5.10. Only the marketing and the nomenclature would change.
What about Perl 6? Well, Perl 6 isn't really the next version of Perl 5, right? Perl 6 is a language specification, and Rakudo 1 is an implementation of Perl 6.x. I don't see the Perl 12 nomenclature interfering with Perl 6 or its implementation(s).