hey pavlo,
amazing work !!
I think I just found the design of my router (well,,,almost!)
I wish if you could send me your design ,I'll start a new thread soon after finishing the initial design of mine.

I'm thinking of ACME (multi-start) instead of ball screw and aluminium (tube) for frame

3-axis upgradeable to removable 4th-axis (rotary)
with a working area of 400mm x 300mm and 2 N.m steppers
I'll order the steppers kit soon
this is the link
http://cgi.ebay.com/4-Axis-Nema-23-S...item4155c86bd7
chinese , can't imagine the life without them

hope to hear from you soon

excuse my bad english ,it's not my native :)