I printed this single print on my single extruder Davinci 1.0 in two colors. Half way through I paused the print, then I left the red cartridge in place but removed the red filament and fed in green from a second cartridge on the side of the printer.

This allowed me to print in two colors. See the results at my YouTube Channel. (I suggest supports so the letters turn out better).

http://youtu.be/4fC5JwKFIiE

Print the MerryChristmas as normal and then half way through the print, remove the red filament from the extruder and load green. The key is to keep the original cartridge in place or else the Davinci 1.0 will cancel the print.