dww and i have discussed functionality similar to this for project*.  when implemented, it might go something like this:

1. visit a results page from a search in the issue queue (/project/issues/user, for example)

2. click on a 'download results' link at the bottom of the page

3. project* goes through the issue list, pulls the issues and related patches, packages them up into a .tgz, and presents them for download.  the structure of the resulting files is not totally clear, but most probably the easiest thing is simply a locally browsable mini-site, with the main page just a listing of the issues similar to the issue search page.

4. for extra bonus points, clicking on any of the 'reply' links in any of the local issues would open an e-mail template which could be used to post a reply via a mailhandler functionality.

of course this is all total vaporware atm, and we have a very large checklist to get through before we can look at implementing it. however, i wouldn't be sad if somebody with some free time decided to file an issue w/ project* module and take this on now.  :)