The latest beta versions of Carbide Motion introduced “Quick Actions”, which are user-defineable G-code snippets. So while not what you are looking for, they may be useful as a workaround (e.g. you could have a macro for surfacing over an X/Y/Z area, and “just” edit it from within CM to match the X/Y/Z values you just measured. This could be somewhat quicker than going back to the CAD computer and re-generating a gcode file).
From this discussion, actual scripting might not be on the horizon yet.