Awesome, simply awesome. Build what you can with what you have is the epitome of American ingenuity. I worked in the machine tool industry for many years, and the advancements in CAD/CAM are just stupendous. I wish we had this 20 years ago. 3D printing combined with precision investment casting combined with CNC machining, and you can literally create anything you can dream up. Just like the PC in the early 80’s, desktop manufacturing has gone from unobtanium to something you can accomplish with ease in your spare time and an idea.
For my money, the best approach is the QU-BD combination machine.
It is designed to do both "positive" 3D by means of thermoplastic deposition AND "subtractive" 3D by means of standard CNC milling. Swap the plastic extruder head for a high-speed milling motor to switch from "positive" to "subtractive", with all the rest of the frame and motion control elements in common.
Fully assembled....$1700.