OK I have started to design my new laser, so far this is what I'm going with-
1) 5/8" feather shafting mounted on end supports
2) cutting area of 24" x 48"
3) nema 23 frame stepper motors
4) belt driven X and Y
5) simplicity linear bearing with my own billow blocks
6) 20w RF co2 laser w/ 80 volt power supply