AFAICT from the ordering guide this is not possible.
By keeping all the wonderful sporty goodies in one option package (M sport steering wheel, sport seats, paddle shifters, etc) I think BMW USA is trying to entice more people to pay for the M Sport package, thereby increasing profits.
Otherwise I would have gotten the basic model and simply added Sport seats; sadly that's not possible here. So I got the M Sport package. I had no other choice, since the during my X1 test drive I discovered the standard seats are too small for me.