I've seen the schematic on the Tele-Q website as well as the Farmermike post from two years ago. I'd rather buy than build - anyone know of anybody who sells the multiple ringer??
I think it is pretty much a DYI thing. If you won't want to build the thing, find someone decent with a soldering iron.. they could crank it out for ya pretty quick. It really is a rather simple box. Would it be possible to re-patch the phones to ring them or is it something that happens rather quickly between rings?