Yup, I haven’t jumped into leather craft too much yet but had them leave the cut out for the kitchen sink when they put in granite countertops just for that purpose.
SlugSlinger, how much are we talking about? Not a whole lot of use for countertops other than, well, countertops. You could make yourself a fancy grilling area/outdoor kitchen. Maybe benches for the yard.
My dad used the granite cut out from my parents kitchen sink for leather work as well. Worked real well.