With already existing routes, I would presume that you would need to add a filter with 'before' then prefix the "url" passing it back to the original route.
So in routes.php, something like:
Route::get('login', 'user@login', array('before' => 'guest'));
Route::post('login', 'user@login', array('before' => 'guest'));
Route::get('logout', 'user@logout', array('before' => 'auth'));
Route::filter('before', function()
{
// Do stuff before every request to your application...
$url = "test";
$controller = "user@test";
$filter = array('before' => 'guest');
return Route::get('/v1/' . $url, $controller, $filter);
});
But I'm not sure how you can fill in the $url, $controller, $filter with the incoming request (maybe Request:: has something).
Though I'm new to Laravel too, and haven't looked into Events and Filters yet.