You can subclass Module::Build on the fly using the subclass method and override the methods that perform the actions. You may need to read through Module::Build::Base to find the methods you want to override, but the general pattern is ACTION_ followed by the name of the action you'd put after "Build". Here's an example of how it would work for install:

# Build.PL
use Module::Build;

my $class = Module::Build->subclass(
    class => "Module::Build::Custom",
    code => <<'SUBCLASS', );

    sub ACTION_install {
        my $self = shift;
        # YOUR CODE HERE
        $self->SUPER::ACTION_install;
    }
SUBCLASS
            
$class->new( 
    module_name         => 'Your::Module',
    # rest of the usual Module::Build parameters
)->create_build_script;
[download]

See the Module::Build::Authoring pod in any of the 0.27 developer releases for better documentation on this.