* Allow depothelper to run on Linux, but obviously in a limited fashion.
  It would just be used to download/cache depots and since it can't get
  a list of installed depots, it would assume that it would need to
  download all non-cached depots it needs to satisfy a package and its
  dependencies.

* It's probably not great to rely on a "true" FTP proxy (e.g. ftpproxy)
  to do proxied downloads. It may be better to look for links, lynx,
  wget or curl and use one of those in preference to FTP if it's
  available. The problem with this is that all those programs have
  multiple dependencies themselves (chicken and egg)...
