Feel free, I don't have enough time to clean it up and push to CPAN… Two comments on your code:

 * I would rename to Dancer::Template::Mason, given that the name of the module is Mason, not Mason2.

 * Drop the data_dir part from your code: Mason defaults are safe enough, no need to add different semantics at this layer, the user can always make his own mind and change the config.

Bye,