I've used an Audrino Mega 1280 with RAMPS 1.4 Sheild and wired from this to external Gecko G251 Stepper Drives. Only one stepper driver is fitted so far as I wanted to test that it would actually work before purchasing all four.
A few things still to do;
Limit switches on all axes
X belt idler
Waiting for 2x more stepper motors to arrive
Waiting for 3x gecko drives to arrive
Machine heated bed
Belt tensioners for extruder
Extruder nozzle heater and thermistor
