They (manufacturers in Asia) used to offer these for the 5-Seater Model X. Why did they stop? Don't know. They are still available for the 6/7-seater car. (See...
WTB: Lower, Sub-Trunk Molded Rubber Mat for Legacy Model X 5-Seater
WTB: Lower, Sub-Trunk Molded Rubber Mat for Legacy Model X 5-Seater