Chip's remark on defining what is to be Certified points to a big reality-check. Many working projects can't be defined, and thus won't certify.

Per Chip; yes, it would be a big project, and a tough nut. The benefits, though, could - would - come to more, and I'd say a lot more, than just ending up with a Certification program.

Per Jeff's latest, Dries Buytaert at Drupal in his 2009 piece plays-down the certification idea. In the second piece, near 5 years later, he applauds its arrival.

Lotta water under the bridge, at Drupal. Buytaert roughed up his people hard, by bringing in hired-gun programmers, ripping out familiar code en masse, and suffusing Drupal with a new framework & methodology. These are part of the price of making the project certification-ready. Drupal was a notorious hairball; undefinable in many ways.

WordPress and Drupal are different products. What works or makes sense for the one, will have to be 'taken on advisement', by the other. But, likewise in the fairly recent past at WordPress, there have been sobering structural code & resource-organization issues, which would have red-flags carpeting the field of play in any attempt to create a 'real' certification system.

I don't know that Baytaert's tactics would fly at WordPress, but WP should have options that will work for it. They won't be cheap nor easy, though, or they would have been done years ago.