Actually no - the syntax of given can not be implemented in Perl through a module¹. You can use source filters to rewrite the program, like Switch did, but you will then get all the problems that are associated with source filters.

¹ Discounting Devel::Declare, which for Perl 5.10 tries to allow new keywords through modules.

Update: Arunbear tells me that Devel::Declare only requires Perl 5.8.1, so modifying the parse process might be possible even there.