I've never seen any regs permitting the absense of touchdown zone RVR. Our SOP says we must have required RVR at all relevant points. Touchdown zone is ALWAYS a relevant point but mid-point maybe reduced and stop-end disregarded.
Thus, for a long runway, touchdown shall have the required RVR and, as the speed will be much reduced by the midpoint, this RVR may be reduced and the stop-end disregarded because it is in excess of the required runway length.
What airport were you thinking about LEM and what company?