The problem of dynamic packages can be solved by a string eval()

my $pkg = "Foo";
eval qq{
    package $pkg;
    sub new { bless [], shift }
};
print ref $pkg->new;

__output__

Foo
[download]

However this is a pretty nasty approach (I'm using string eval() for the love of ...). But if you're just attaching methods and attribs to a package in a fairly starightforward fashion you don't even need the package declaration

my $pkg = "Foo";
{
    no strict 'refs';
    *{"${pkg}::new"} = sub { bless [], shift };
}
print ref $pkg->new;

__output__

Foo
[download]

Now you can have your dynamically created package just by fully qualifying the likes of subroutines and variables. So while it's possible to do what you want (this is Perl afterall) the question begs to be asked: why would you want to?
HTH

_________
broquaint