use 5.010;
use Class::Load qw/load_class/;

sub compose
{
	load_class($_) foreach @_;
	
	# Note "state" is Perl 5.10 mojo. For back compat, use
	# "my $count = 0" OUTSIDE the sub definition. That is,
	# create a closure over it.
	state $count = 0;
	my $package = sprintf('%s::__COMPOSED__::X%04x', __PACKAGE__, ++$count);
	
	{
		no strict 'refs';
		@{"$package\::ISA"} = @_; 
	}
	
	$package;
}

my $class = compose(qw/LWP::UserAgent Data::Dumper/);
say $class;

my $obj = $class->new;
say $obj;
say $obj->can('agent');
say $obj->can('Dumper');

# Or even...
my $obj2 = compose(qw/LWP::UserAgent Data::Dumper HTTP::Request/)->new;