You can still build a system with Moose and dynamically include other modules via require. I don't see why you would want to use "dynamic inheritance," however -- simple aggregation should get the job done and those classes could inherit from a base class. Better yet -- try Moose::Role.
If you have more questions, please consider posting some code for reference.
It now works, thanks to Moose::Role. I tried Moose::Role before but it didn't work. I think I made some errors with the namespaces of the files...
I thought about using a "simple" require but I can't stand the thought of using something that's not included in the Framework. I mean where's the point in using it if you just write the code like you did before?
Another error I made was calling make_immutable on the controller-class which results in an error because inheritance is not working after calling it (no sureprise, if I think about it ;( ).
Here's the part of my programm which includes the other class (as a role) and then calles the corresponding config_module sub in the inherited class.
sub load_config {
my $self = shift;
my $to_load = shift;
with "LaborBelege::AddOns::$to_load\::main";
$self->config_module();
}