A Pattern for Reusable Repository Design in Laravel - http://www.slashnode.com/reusable-repository-design-in-laravel/

UserRepositoryInterface.php

<?php namespace Acme\Repositories;

/**
 * The UserRepositoryInterface contains ONLY method signatures for methods 
 * related to the User object.
 *
 * Note that we extend from RepositoryInterface, so any class that implements 
 * this interface must also provide all the standard eloquent methods (find, all, etc.)
 */

interface UserRepositoryInterface extends RepositoryInterface {
	
	public function findUserByUsername($username);

}