A great project in this vein is the Hive retrocomputer [1], which features three Propeller chips from Parallax organized as a master and two slaves. The project "official" language is German though.
Since the request and response sizes can reveal what public page you are browsing over https, OE in the proposed form would not prevent user tracking: http://sysd.org/stas/node/220
> I don't want to use a client without conversation view, and Thunderbird doesn't seem to offer it as a core feature
Actually it does, sort of: Right click on [email protected], choose Search Messages, then Save as Search Folder, then "Match all Messages" and, in "Select the folders to search", Inbox and Sent.