[kbenson]

That sounds like most the old webmail clients of yesteryear, except for speed. Squirrelmail was pretty bare bones, but worked. Beating Gmail for speed is going to be hard unless you work with some non-traditional backing storage.

If you really, really want speed, simplicity (beyond initial learning curve at least) and access, getting access to a host that allows shell access, has mutt and screen or tmux installed, and accepts mail delivery would hit all your points as long as a SSH session is doable. Screen/tmux keep the client open when you are disconnected to speed (no need to scan a few hundred MB or couple GB of messages in mbox or Maildir format), and mutt will be as fast and configurable as you can imagine (plus you generally get procmail).

If you're actually interested in that and don't want to run your own mail server, sonic.com (used to be sonic.net) has free shell accounts for customers, and they have non internet services you can sign up for still I think (such as hosting). In any case, you can just call or email support and tell them you are looking for a shell account to read your email and they might hook you up with a shell account for a couple bucks a month.