Drupal is one of the most popular content management systems and modular web application architectures available.
It would be an excellent system to deploy an RPM management system on. This system would generate .spec files for the modules, ensuring dependencies could be enforced and allowing the use of yum or other methods to automate upgrades.
The success of this approach for developers would be dependent upon their ability to architect their implementations without modifying Drupal and interfacing correctly to the module system.
It also requires that Drupal serve as a server component, rather than just an account-level application. Managed carefully, with configuration files and other innovative methods, rapid deployment of manageable Drupal sites would be extremely cost-effective.