Just letting everyone know, that there is a new Drupal MVC framework called Drupal Prometheus. We have been using it extensively on a past project and it's awesome. It has advanced URL to namespace/class/function mapping support, input data filtering and validation and also comes with presentation layer that's either region or full page based. It's loadable as Drupal CMS module. Check it out at http://www.drupalprometheus.org

Thanks.