Implemented a database-rule-driven product configurator, as part of a migration of the Rig-A-Lite site to Drupal 7. Rig-A-Lite provides lighting solutions for hazardous environments, such as light fixtures for off-shore oil rigs. Their old product configurator did not enforce legal configuration choices - such as which ballasts require fuse blocks, or are not available with metal halide lamps, for example - which caused order processing aggravation for their worldwide sales reps and customers.
The configurator is iframe'd into Drupal, leveraging the company's old sophisticated full-custom PHP/MySQL/JQuery CMS backend to populate its new Drupal front end. The new rules data is edited in a valid-configurations Excel table, and imported into the CMS, to drive the product configurator user interface.
As of this writing, most products haven't been converted to use the new configurator. That was a design feature, that the new system would allow them to use both old and new product configurators side by side, as they gradually converted products.