This is duplicate of bug#217217.  I couldn't see a way to append additional 
comments to it.

Basically, I'd like Evolution to support per-folder From: lines.  I'd like to 
use Evolution to manage my FreeBSD mail (where I'm nik@freebsd.org), 
my corporate mail (nik@crf-consulting.co.uk), "Home" (nik@ngo.org.uk), 
and a bunch of others accounts (nik@slashdot.org, nik@multiplay.co.uk, 
and so forth).

This is trivial to do in Mutt, where I have folder-hooks that change my 
outgoing e-mail address based on the folder I'm currently in.  If I switched 
to Evolution I would have to remember to select the correct e-mail 
address for every single message I send out.

In #17217 Jeff Stedfast says:

> I feel that this probably isn't really needed... when you download a
> message from POP, it adds an X-Evolution-Source header to specify
> which account it was downloaded via and so when you go to reply to a
> message, it auto-detects which account to set as the From address.

This won't work for my situation.  My network IMAP server fetches mail 
from a variety of other sources for all my accounts.  I would only have one 
Evolution 'account', but need support for multiple From: lines.

Jeff also says:

> making it a per-folder option will be VERY painful and not provide
> much extra benefit (the only benefit you'd get is that if you composed
> a *new* message it would choose the default from account but in cases
> when replying, it would provide 0 extra benefit)

That's also not the case.  People occasionally send me business mail to my 
FreeBSD account (because that's how they heard about me).  The first thing 
I do is move the message to my business mail folders.  Then I reply, and 
Mutt does the right thing, and selects my business address as the From: 
line.