Is it feasible to have an SMTP server change the FROM address of an e-mail, concealing the master account?
POBox told me that it was possible with their service, depending upon "exactly how you set up your e-mail client".
If you have that, you can make use of an e-mail forward or mailing list attribute of your smtp server. If you Google finest smtp server, that server really has the attribute of mailing list and you can set up a mailing list with simply one individual in it so when you send an email to that list, its going to be forward to that person and "From:" e-mail address is going to be changed to the From: e-mail address of the list owner.
You can change the "from" address on either the client or the server. This is what makes spoofing email so easy.
However it's not so easy to change the send-by headers which say what server sent the email.
Most of that kind of email will also go into spam, since these days with the advent of domainkeys and spf, the big email players make it harder and herder to spoof emails.