MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I've posted more details here: http://fpv-community.de/showthread.php?67660-Baubericht-Umbau-Prusa-i3-zu-Laser-Gravierer-(inkl-Firmware-f%FCr-samelladrucker)
You may want to use google translator or just visit http://jtechphotonics.com/?page_id=1503 for more.
Focusing is done by adjusting the lasers' lens or the Z height via gcode or display if you have that connected... Or just turn the two Z couplings manually. After all this is not much of a problem.