Mailpile mailpile mailpile!
So I'm still obsessed with Mailpile.
Part of the problem is that people keep encouraging me: Smári has met with me twice this week to hack on it, and Björgvin once.
The program has also made rapid progress (at the expense of other things), it now sorts and threads and has persistent settings and a basic text-based user interface.
I've revised my estimates of how much e-mail the Python code can handle up to about a million messages - after the latest optimizations that much mail would only take about 250MB of RAM, which isn't bad at all. Of course at that scale, some search terms will have a lot of results and processing them won't be instantaneous. But it will still be pretty fast. :-)
Mailpile is fun! It probably needs a better name though. Got any ideas?