Alicia Gibb of OSHWA and I (I'm on their board) cooked up the idea, chatting a few months ago, of a "spec" for a file similar to the CONTRIBUTORS or CREDITS text files found in some FOSS projects -- a kind of text file format for describing your project and providing key information. So, a little broader than just listing contributors, but really fulfilling all of the Open Source Hardware Definition. As it'd be machine readable, it could form the basis for a repository -- the URLs to these files in different peoples' online posted docs could be scraped and indexed.
This sample has a lot of ideas, some better than others, but the most minimal example would be really short; just
Link to Gist example: https://gist.github.com/jywarren/a4dafb0f02e731eacb14
What do you think? It's a slightly more concrete way to kick off any discussions of repositories, and people could begin creating these "contributors.json" files now, which could help in later attempts to create a more comprehensive directory of open hardware projects.
Basically this is just a rough proposal, but it wouldn't be too hard for Public Lab tool pages to provide such a standardized JSON file, and perhaps others would adopt it as a draft standard?