Purrrrfect. That's what I was hoping for.
The DSL account here will handle the mail just fine, but for the system I will want to be running, cable would be a better option. Sadly, cable doesn't support a static IP (which is nothing that DDNS can't fix), which ends up meaning that outbound port 25 is restricted. That's nothing that a little route-around through the existing DSL line for the household internet can't fix though.