Well, I've tried a couple of things... nothing will quite work.

There's the "import single file" approach from within evolution, but I don't seem to have a file in the right format in my .thunderbird directory.
My last effort was to simply send all my mails as attachments to myself... now I have a bunch of eml files and attachments all scattered in one directory, and no idea how to get them in my inbox.

Those mails represent about 3 months where ubuntu went belly-up, and I received all my mail on my eee-pc, and thunderbird deleted all the mail from the server although I believe I specifically told it not to do that... so now I have to merge my evolution backup (already restored) with the hundred or so mails from thunderbird.

Help much appreciated.

Last time I did a mail migration, I installed BincIMAP, which is about as simple an IMAP server as can be, and configured access to this local IMAP account in both mail clients.

I copied all mail from the “Local folders” account to the IMAP one, and it is still there. IMAP is very handy: all your mail available in any IMAP-aware client; you can change your email client twice a day if you want!

BincIMAP makes your email available through IMAP and stores it in a Maildir/ directory in your home folder, in Maildir format. Many advantages:
— The mail is in the home folder, so any backup of your personal data also includes your mail.
— IMAP: see my comment above about choice.
— Maildir storage: you can thus use text-mode clients that read the Maildir format when you connect remotely, or use new-mail-notifiers that know of Maildir, but don't handle IMAP.

Yves.

I forgot to mention that Postfix handles delivering incoming mail to BincIMAP's Maildir/ directory very well, which makes Postfix+BincIMAP a complete and very functional small-scale mail solution.