Re Weather Tech mats: If you go to their website<www.WeatherTech.com> there is a place to contact them regarding new products. If enough smart owners contact them, they will likely add smart mats to their product line.
I bought the smart trunk tray at smart center Cherry Hill, and am very happy with it. There are several other trunk additions in the printed smart catalogue.
I also added the luggage compartment cover from smart. Nifty. And, it reduces engine noise in cabin a bit.