Since they're all moving at the same time, you could simply drive the inputs in parallel (ie: hook up a bunch of driver boards with their minimum components, connect step/dir/enable in parallel to some Arduino pins, then just do your movements).
There is nothing special about the wiring on a RAMPS or Megatronics board with regards to using the A4988's or DRV8825's.
The reason most of the RepRap printers are fairly quiet is that they're using microstepping when driving the motors. The A4988's have a max microstepping of 1/16th, while the DRV8825's have a max microstepping of 1/32nd. The DRV8825's also handle a little higher current motors, so it's what many people are using now, and what I'm planning to use on my next machine. Also, most stepper drivers are least accurate at their max microstepping setting, so you can run a DRV8825 at 1/16th step and get more accurate microsteps than out of an A4988. I don't believe this is MUCH of an issue, but if you're really worried about precision, definitely keep it in mind.
Here's the product page for the Pololu DRV8825, which has PDF datasheet that covers how to hook it up and use it. [www.pololu.com]
PS: There is a simple way to set the motor current using a voltmeter (measuring the Vref pin on the DRV8825 board). You need to know your motor current specs and make a simple calc to figure out what it is, then just adjust the trimpot so that Vref is the value you calculated. Details should all be in the spec sheet. If you have issues, feel free to ask.
There is nothing special about the wiring on a RAMPS or Megatronics board with regards to using the A4988's or DRV8825's.
The reason most of the RepRap printers are fairly quiet is that they're using microstepping when driving the motors. The A4988's have a max microstepping of 1/16th, while the DRV8825's have a max microstepping of 1/32nd. The DRV8825's also handle a little higher current motors, so it's what many people are using now, and what I'm planning to use on my next machine. Also, most stepper drivers are least accurate at their max microstepping setting, so you can run a DRV8825 at 1/16th step and get more accurate microsteps than out of an A4988. I don't believe this is MUCH of an issue, but if you're really worried about precision, definitely keep it in mind.
Here's the product page for the Pololu DRV8825, which has PDF datasheet that covers how to hook it up and use it. [www.pololu.com]
PS: There is a simple way to set the motor current using a voltmeter (measuring the Vref pin on the DRV8825 board). You need to know your motor current specs and make a simple calc to figure out what it is, then just adjust the trimpot so that Vref is the value you calculated. Details should all be in the spec sheet. If you have issues, feel free to ask.