It's not really the size of the machine that dictates how large motors you need, but rather what you want the machine to be able to do. You could build a huge, lightweight, slow machine for cutting say balsa with a dremel and use quite small motors, or you could build a small machine for steel work and then you would probably need bigger motors.
The strength of you motors together with gearing and the type of screw you use, and the weight of your gantry/table, is what decides maximum acceleration and speed.
Oh, by the way, writing in only capitals is CONSIDERED SHOUTING
good luck
Arvid