sixtharmy,
Let me throw in my 2-cents
I'm still not sure what you intend to do but it appears that:
1. You've been able to figure out how to drive the Epson printhead directly (POSAM...)
2. You're very familiar with programming.
That being the case, why not just attach the Epson printhead to a normal XY(Z) CNC machine and just write the software to control the movement and trigger the printhead. Most CNC are step/dir driven so it's easy to locate the printhead to where you want it to be. If you're electronically inclined, may be make a simple PIC/AVR controller to 'translate' Z-axis movement into printhead firing sequence thus allowing you to use the off-the-shelf G-Code translators in the market (Mach2, TurboCNC, etc).
I'm keen to get this going but the epson printhead mentioned is too pricey for my butcher knife
What are the disadvantage/limitation of other (cheaper) printheads?