FWIW, Crestron has some goodies that will do the trick (20 Amps) at about
$80/port + controller (per site). We're trying to get them to add some
voice-response DTMF control capability. Might be good to call them and
tell them you're an ISP that would be interested in what ConXioN has been
asking for. Might help to convince them there's a market for it.
Their specialty is remote control for theater/auditorium lighting and audio/
visual stuff, but their solution looks pretty keen. They're really close
to exactly what I'd want.
Owen