I am not sure what your plans are for Drupal 7, but I have a module (Search by Page Attachments, part of http://drupal.org/project/search_by_page) which depends on Search Files API. Since I just ported my module to Drupal 7, in the process I also ported the API portion of your module to Drupal 7.
I'll attach it in a zip file in a comment here in just a second. I didn't think making a patch file was all that useful.
I also didn't port the other modules in your project, just the API module.
Hope this helps...