You seem to already be using Riseup, which is great. :)
http://www.fsf.org/resources/webmail-systems may be of interest.
Thanks for this link. Somehow I missed this in my search.
I have almost no spam problems on a self-hosted setup using
SpamAssassin
(after very little training) plus DNS blacklists (spamhaus, surriel,
spamcop).
This was exactly the system I was using. My spam issues were caused by
an IP address with a sordid history. Maybe I should be asking about
libre VPS servers. At my home I unfortunately have a dynamic address.
The time-consuming part is setting it all up, and it sounds like
you've already achieved that.
Perhaps I should find a new VPS and get going again. From the sound of
it, it seems that a lot of folks are running their own email servers.
