At that size of machine, I wouldn't even consider steppers.

You can get 1kw servos for well under £200 an axis, which would give you far better performance, and removes the need for any DC supply.
Have a search for Lichuan Servo on Aliexpress for rough pricing, but contact Lichuan directly via Alibaba, and they'll usually do a better price and customise the order for what you need (i.e.cables whatever length that you need).