i don't think that you would find anyone who is opposed to such a tool being created.
Just the work of identifying the different types of access, enumerating them, and maintaining a list of per-ISP configs would be of immense value.
then configuring MTA or MUA software from that data would be much easier.
and by the way, as long as the actual work of configuring the MTA/MUA was modular and scriptable, this would also fit into the "Unix way" quite nicely :-)