So Im looking into and learning more about long ballscrews and how to run them. Obviously spinning the ball nut is a way to go but each unit gets to be pretty costly by the time you are said and done.

Another thing I found was supports along the ballscrew which effectively push the critical speed to a higher rpm. Has anyone ever looked into this type of design?
http://www.linearmotiontips.com/achi...d-ball-screws/

Thermwood does this on the long axis of some of their CNC machines. It looks like the support flips as the ballnut passes and then supports the ballscrew again on the other side of the ballnut.
Click image for larger version.  Name: Thermwood CNC.jpg  Views: 1217  Size: 120.9 KB  ID: 17899

I assume these are just nylon but cant find any further details on this type of support. I wonder if it could be considerably less expensive to incorporate this, provided the same performance is achieved in the end. Thoughts?

So still learning about the CSLabs IP-A and trying to decide if the extra money is worth it. With all ballscrews, I dont know that there will ever be a time that the system could move while the drives are disabled? I.e. I would have to manually turn the ballscrew or the motor to put it out of position. However, if Mach knows absolute position does that mean that the system needs to be "homed" less often? Between cuts etc. Are there other benefits to having Mach know the absolute position from the resolver? I hope to make a decision here soon on a motion control card... If anyone has any further thoughts I greatly appreciate it.

Thanks to Fred over at BST for working with me, I have ordered motors, 2 for X, 1 for Y, and 1 for Z. I decided to go with servo on Z as it seemed silly for the price difference to have that axis be a stepper.

Next up is HTD timing gears/belts just need to figure out speeds and gear ratio. Thanks Boyan for posting the 20t:30t Starting point and after putting it on paper sure makes sense to me.

So some math just to make sure I have things right
Lets say 20000mm/min travel
Ballnut is 5mm per revolution

(20000mm/min ) / (5mm/rev) = Ballscrew rpm => 4000rpm

Gear ratio 20t:30t = 0.666

4000rpm * gear ratio => Motor Speed => 2666rpm.

The motors I purchased from Fred are 3000rpm so this looks reasonable to me.