Your aiming at a somewhat different goal to me, in that my package don't exist as files and only come into being when they are used, but I really like where your going too.

I'm not sure if it fits with your intent, but I really like the idea of

use WhenNeeded qw[
    HTTP::*
    HTML::*
];


my $headers = new HTTP::Headers;
...
my $request = new HTTP::Request;
...

my $content = decode( $content );
[download]

But maybe that syntax is just too Javan :)