Should've mentioned that I can host on my server.
I checked out project pier, it seemed suitable, except for that its wikis were rubbish. Redmine and trac seem like projects unto themselves. Ultimately didn't care for Wunderkit or Teambox. Dropbox, also meh.
In the end I'll be using a phpbb installation (it's basically a one-click set-up from my cpanel). There will be a forum that serves as a script repository. Each thread representing a script will link to a google doc whose share settings allow anyone w/ the link to edit it. Users will also be able to upload files on the forum, w/ each post obviating that its iteration is more recent than the one before.
Thanx for the suggestions, they helped even though I went a different route.