The aim of of the WikiProject Structured Data for Commons is:
To develop templates that draw directly on Wikidata (and in future also on Commons Wikibase), that will act as drop-in replacements for templates currently in use on Commons.
To develop new templates that can bring new functionality to Commons filepages (eg "topics" listings)
To support the cataloguing of particularly idiosyncratic templates currently in use on Commons (eg institutional credit/backlink templates, and other source templates), and try to produce more generalised, standardised forms that can draw on Wikidata.
To work with other WikiProjects on Wikidata to understand, document and develop the data models on Wikidata, and make sure that they are sufficient to accommodate the needs of GLAM organisations and others currently or in future uploading or maintaining metadata on Commons.
To start to port existing such data that can be represented in structured form, and is appropriate to do so, from Commons to Wikidata
To examine the divide between what should be stored on Wikidata and what should be stored on the proposed Commons Wikibase.
It is now possible to develop templates here on www.wikidata.org using Arbitrary Access -- ie to prototype templates accessing Q-numbers other than that belonging to the page itself. This functionality will not be available on Commons probably before early 2015.
Also there is a need for a space on Wikidata where Commons users can come together and work together to get the most we can for Commons out of Wikidata. This project aims to be just such an all-inclusive user group for Commons users on Wikidata.
-- a prototype template to let us test how to display a set of "topics", each topic being a Q-number, with options eg just to display a count of them; or to display a list of their names; or a list of the topic names with mini-descriptions.