Yup you can make your legs go into your table to make an adjustable MPCNC.
Wait, what? That’s interesting! You said earlier in the thread that Z-axis is the critical dimension for a rigid tool. If I understand you correctly, here it sounds like you’re saying that the extra Z is only bad if the tool is hanging down on a long cantilever; if you shorten the legs so the tool is never lowered far from the Z gantry, then you get all the rigidity benefits of a short Z axis?
If my understanding is correct, then it might make sense for me to build a bigger Z (say, 8″), and just stick some short conduit in the machine legs to shorten Z travel to 2″ when I want to try milling aluminum.