I'd go for a Ramps / Mega combo for the electronics. That cuts out pc board layout and a lot of firmware work. It scales the project back to the point that you might actually be able to get it done. A full set of steppers costs around $75 if they are normal NEMA17 motors. The Mega can be a $15 clone from eBay, they all seem to work ok. The Ramps board it's self is about the same. You can find the Ramps in combination with the stepper drivers for about $40 or so.
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Of course for $600 you could by a full blown printer kit and build it ....then you are sure to have a woking gizmo when you are done.:)-D
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Of course for $600 you could by a full blown printer kit and build it ....then you are sure to have a woking gizmo when you are done.:)-D