You're never going to get 1200ipm with those screws and stepper motors. In most cases, stepper motors have a maximum usable rpm of about 1000rpm. Absolute best case would be maybe 1500rpm, but that's very difficult to calculate. Depending on your acceleration rate, you might be limited to 400-500ipm with steppers. Acceleration rate is actually what determines your maximum speed. Steppers lose torque as rpm's increase. Acceleration requires a specific, constant force. To accelerate at a given rate, you can only accelerate up to the point where you run out of torque. The faster you accelerate, the more force that's required. Which means you'll reach your available torque limit sooner, resulting in a lower top speed. SO basically, the faster you accelerate, the lower your top speed will be. Most machines I see that can rapid at 1200ipm use rack and pinion, and don't accelerate quickly enough to even run at 1200ipm. As soon as they get to 1200ipm, they need to start decelerating to come to a stop before they run out of room.
Maximum no load rpm is meaningless, because your motors would need to see the maximum load to get to that rpm.
It's very difficult to choose the peerfect stepper motor for a given application. Mainly, becuse it's nearly impossible to get an accurate torque curve for the spcific motor/drive combination you might be looking at. Without an accurate torque curve, you really can only guess at how much torque you'll have at any given rpm. This is the most important information in choosing a stepper motor, and you really don't know what it is.
Stepper motor maximum voltage should be no more than 32 x sq rt of the motors inductance. Any higher results in excessive heat and no performance gains.
If you're going to use motors rated 3 amps or less, then there is no need to use Gecko G201's. A Gecko G540 can deliver 3 amps and is a much cheaper option.
It's also the most popular option here.
The most popular option you'll find here is a Gecko G540 with 380oz motors that are a good match for them. They are a pretty good fit for most applications in the size you have. If you want to go faster, you have two options.
1) Larger Nema 34 motors in the 450 oz range, rated at 6 amps, and Gecko G201 or G203 drives. These will usually have more torque at higher rpms than the Nema 23's at 3.5 amps.
2) Servos. If you want to spin your screws at 3000 rpm, then servos are the way to go. However, if it were me, my preference would be ballscrews with a 20-25mm pitch, geared 2:1.
I'd stay away from the Kickstarter stuff. I'm not familiar with that specific board, but I've neve seen any high performance CNC components coming from Kickstarter. Most Kickstarter projects are geared towards low cost for the masses, not high performance.
If you decide to go with a Smoothstepper, the ethernet version is a much better choice than the USB version, which is very sensitive to electronic noise.