I randomly stumbled across this post when I looked at "today's posts".
Is this an upgrade for the router you mentioned in other posts? Are you committed to this deal?
4005 @ 2700mm long is a really bad choice IMO for a router. What motors are you planning to use to drive these ballscrews?
A lead of 40mm with gear reduction might work, but I'd have to look at the math.
40mm diameter ballscrews at 5mm lead will have ALOT of rotary inertia to overcome. Machine would be very slow with very low acceleration ability. Unless perhaps if it was paired with huge servos.
Please elaborate on what you're doing if you'd like more of an opinion. I thought about just not saying anything because you didn't ask for feedback, but I also realized that saying something here might really help you out.