TXI: Standards for tables built from multiple XML instances?

A pattern emerging in multiple working groups is the "Table of XML Instances", or TXI pattern; and the question is to what extent IVOA should be involved in standardization. Three examples have emerged: Regions, Resources, and Events. IVOA already has a standard XML description of, for example, a sky region, including observation location, coordinate frame, etc etc; but if there are 100 regions, all quadrilaterals of the same frame and observation location, then it is much more efficient to put common material at the top of a table, and the table rows hold what is different between the instances. Similarly (in NVO at least) a quasi-standard is emerging for a table of registry resources, rather than handle the complexity of multiple VOResource instances. The same is happening as a set of homogeneous VOEvents is rewritten as a table. The question is whether IVOA should standardize such TXI representations.