I don't have anything to add to the other response to your MAILTPL
question, but I thought I'd briefly touch on the other questions:

>2) Is there any option to have, similar to Majordomo, listserv to put
>(anywhere in the message) a line something like:
>
>This message sent by:  <name> <addy>

I did a little testing and there doesn't seem to be a way to do this.
On the other hand, this information appears in the 'From:' header.

>and 3) Is there any option to set, to notify the listowner when people
>change their address with the 'change' command, or when they set
>themselves to a particular option (removing the ADMIN topic, setting to
>nomail, or especially, conceal).  I am not hopeful with this last one, but I
>thought it couldn't hurt to ask. ;)

Not for changing options, but for the address change thing you should
be able to accomplish this by modifying the CHANGE1 mail template to
include the following lines:

| .TO &WHOM .CC &OWNERS

or similar.
--
Jacob Haller, Technical Support
L-Soft international, Inc
http://www.lsoft.com/