A useful metaphor is a pilot's license; treating certifications like MCDBA, J2EE, UML, etc. in the same way makes a lot of sense. You get you basic pilot's license when you've completed the basic course and soloed, usually in something like a Piper Cub. Then you get additional endorsements attached to your license by taking further training and testing, such as multi-engine, commercial, jet engine. It is also possible to get certified on a specific model--you can have an endorsement to fly 747's, even though you're not qualified to fly any other type of multi-engine airplane whether jet or propellor driven.

Having MCDBA as the basic certification, and then getting endorsements for Replication, Clustering, OLAP, DTS, heterogenous environments and other topics makes sense. The first endorsements could correspond with the optional exams that you took to get the basic certification.

This would give a good framework for relating experience and certification with client needs.