late binding approach to taxonomies and properties

as suggested by @pipauwel, lets open a new thread. I will label it both as **enhancement** and **governance**, because it can only be answered having both in mind.

**enhancement** - what would be the right way to:
a) publish the "late binding" content as part of the internationally agreed IFC specification (and ISO 16739)
b) reference from within the IFC structure to its external "late binding" definitions

**governance** - how to ensure that:
a) the definitions that are currently in IFC (like the IFC class structure underneath IfcProduct, that is the baseline of many exchanges today and that is currently strongly enhanced for infrastructure) are internationally maintained as part of the IFC specification (specification =/= schema)
b) that those definition can easily enhanced by national, regional, trade, etc. definitions using the reference structure from within the IFC

bSDD is a "theoretical" answer, but not a "practical" answer as of today. Any thoughts?