software/hardware for laser engraver

I am using EMC on a large 3 axis bed mill. I want to mount a small
(25 watt) CO2 laser and galvo head to the mill head (the mill head
moves up and down on boxed ways, is already 500lbs by itself, so a
few more pounds will not make a difference). The galvos take a +/-
10V signal for x and y, for a total beamscan area of 4" x 4". My
idea was that this small area would be scanned across the workpiece
because of the large (28 inch x 16 inch) travel of the mill table.

Anyway, I am using EMC to control the mill, and I was thinking about
ways I could control the laser head. I could make a microcontroller
and D/A board, but I am not sure how to drive it. Obviously the
galvos need to move much faster than any step/direction program can
drive them. I am using step/direction for the other three axis. I
would want to do things like engrave control panels in anodized
aluminum (it ends up looking similar to silkscreen). I also might
use the laser to cut balsa airplan parts and dollhouse parts (a trick
to get my wife to let me buy the laser), but that would be slower,
and I could just let the galvos reside at 0,0 and move the mill
table. With the speed of the galvos, I could also do grayscale
images in wood, which could be kinda cool.

Any suggestions? Is anyone else planning something like this and
would like to collaborate?

Richard