Help: PCB Trace Milling Software

Thanks for everyone's help on CNC Software. Here's more of a niche
question for the group... Does anyone know of available software that will
convert standard Gerber (RS-274X) photo plot files you get out of printed
circuit board CAD software into G-Code for mechanical PCB trace milling?

It's a complex issue as the Gerber file (I believe) specifies an aperture,
start and end location for the piece of copper you want. The apertures
were originally selected from a wheel and light was directed onto a
photosensitive material to "plot" the trace. For a milled PCB, however,
you want to remove copper alongside the desired trace to isolate it from
the other traces. So in effect, the G-Code needs to cut away the copper
you don't want, leaving the traces you do as "islands".

There are some very expensive turn-key systems out there doing this stuff,
but I'm not aware of anyone who has it working at the hobbyist
level. Those who are making PCB's on a CNC mill or engraver, just draw the
entire PCB with isolation tracks by hand in regular CAD software. For a
very simple board, that's reasonable, but for anything more complex, it's a
nightmare in comparison to using a PCB CAD package that works directly from
the electrical schematic and does automatic trace routing.

Any help or even possible suggestions would really be appreciated!

Mike