I've made a 15x15 cnc similar to the microcarve by using a smaller cnc, this might not help though because a microcarve is still pretty small.
I started by making the side panels, I routed it in 2 parts with a dovetail where they meet, then I glued them together. With my router table I used that as a template that I screwd onto another price of mdf then used that to make two side panels. Where the screws were, I drilled the holes for the threaded rods. Then to hold the cross supports I made braces like a c that I glued onto the side profiles. The rest I made with my DIY router table.