I'm not sure about cloth playmats. There's an older, 2-person cloth playmat which is awesome, but outside of that I'm not certain of any.
If you mean rubbery, mousepad-like playmats, then those are huge in other games and are catching on in Pokemon as well. Mostly they're given away through raffles at events, but Worlds qualifiers from this past year earned some, and there's the Prof.-exclusive Darkrai ones as well. Oh, and the winner of States gets one too. Your best bet is to look around on eBay. Pokemon ones are quite expensive, but can be found, and other games' playmats can be picked up for quite cheap. You can also find generic ones, along with M:TG ones in retail stores for not entirely too much.
Good luck!