Whatever you decide, make sure that you don't skimp on the frame. A good 80/20 frame like the one on the mendelmax will be very stable. Many of the problems with earlier versions of reprap style printers were due to flexible frames. There are lots of maker style extrusions available but I find that the original 80/20 type is best for larger printers. If you do go mendelmax, the second version will get you a bunch more clearance on the z-axis. The prusa i3 is pretty much the same so if you do decide to roll-your-own you can mix and match. Wish I had those tools available. Have fun! Does your CNC work with metal or only wood?