Neale is correct it's a little premature to be recommending or even thinking of buying anything yet if you haven't even designed the machine.

The Gecko G540 is a nice bit of kit but it does have some limitiations like restricted to 3.5a motors and still use all it's features, Plus restricted to less than 50Vdc for running motors.
Machine your size if robustly built will most likely be best run on nema23 motors which if sourced in Europe will most likely be 3Nm and 4.2 and for best performance you'll want to run them on 75-80V drives with 65-70Vdc PSU.
The G540 can run 4.2a motors but you loose the Idle current reduction feature which means the motors get hot when at stand still. Also your restricted to aprox 42-45Vdc to leave a safety margin for back EMF.

So my advice is to look at individual drives and don't buy anything yet. Save and wait until you need them then buy good quality Digital drives along with correctly sized PSU.

If you do want a decent all-in-one drive that's slightly higher spec than the Gecko then look at the Leadshine MX3660 which is only 3 axis but as 60Vdc digital drives along with inbuilt BOB and spindle control. http://www.zappautomation.co.uk/elec...ng-driver.html