Hi Rick,
i'm following this "vertical plotter" thing for a quite long time, since makelangelo, polargraph and so on.

I appreciate a lot your idea of not inventing the wheel once more and to directly adapt/extend an already well developed firmware.

In my opinion, like every other projects, there's a basic issue:
this "system" is still hardlinking the physical machine, the control software and the CAM software.
In this way everytime something changes it's not so easy to fix the whole workflow and get ready to print again.

I think that the right workflow should be this:

1. once defined the paper dimension the CAM phase should take place and, if the output is a standard gcode (more or less), this means that everyone with the same paper dimension CAN use the same file.
   In this way i can prepare a file that you can use and everyone can do the same.
   It's actually possible to use a huge number of CAM software, not only the "artistic" cam that is bundled with the makelangelo's or polargraph's software, and to build a huge file database.
2. the control software should be separated from the cam and the firmware, it should take care only of the manual movement of the gondola, the pen servo, the homing procedure (which is firmware related) and to define the starting point.
3. the machine's firmware should take care of the real homing procedure (i'm trying to find a physical solution for the endstops), to parse the gcode (readed from a SD card, possibly), and to actually move the machine.

Do you think that this is something that worths some dedicated developement?
I don't have any programming skills that can help the cam/control software development, but i have a ramps pen plotter, a 3d printer and i'm not a total noob with cnc/gcode/firmware.
Let me know if we can do something!

Marco