Is matrix filed appropriate for arbitrary attribute-value pairs? a two-value-field?

Years ago I did a small module that did this:

but was unable to upgrade it to D6 and the newer database storage methods. I got confused trying to insert two values through the field abstraction layer.

Would this behaviour be within the scope of matrix.module, could it be added, or is it different enough to be its own sub-module, based on what I can extract from the way matrix code works?

DESCRIPTION:
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This module provides a field type for cck that adds any number of user-defined fields.

Intended, for example, to extend a product catalog with structured
descriptions of size, weight, length, and other arbitrary specifications
where some products have them, and other have others - without requiring
a unique product type to be defined for every variation

In the long run, I'm looking towards RDF, and using a fieldset like this for metadata (eg, all the Dublin Core keywords on one side, but none required, and just in a list, not as unique fields) but I'm happier to be working with these as CCK field vales first.