Is it possible to mirror copy a cabinet you already have drawn? Such as 45 degree angle clipped cabinet so I can just draw a left one and mirror it to get the other.
Unfortunately, no. It would certainly be a nice feature sometimes though.
Now you can save the outlines in the Part Editor as an x_t (extended tool) file then mirror that when applying it to the other cabinet. That makes it a little easier than starting completely from scratch,