and maintainer of:
I have just mailed some additions to the author of Date::Holidays::DK. Just out of interest I took at look at the related modules:
There might be more, but these showed up on my first search and the DK variant is currently of most interest in my little project.
But a few things bother me, the naming convention is not consistant and the methods exported are not completely uniform.
So there might be more work for me in order to get all the modules integrated with my little project