I worked with "Maybe Matts" (Spelling...? Mabe, Maby, etc... sounded like "MAYBE") on a power project in St. Petersburg, FL. They were about 8 feet wide and perhaps 12 feet long. They are used for turf protection in the ROW and work real well. They are maybe 2 inches thick, like hard plastic on top, and softer, almost rubbery on the bottom, where the mat meets the turf.
Apparently these things are available across the globe for regional retailers for both rental and purchase. I remember thinking they were about 7 bucks per day to rent, which isnt bad if you only need a few for a quick project.
I think they were like 170 bucks each to buy, which is a little steep, but they seemed real durable.
The regional dealer sends a truck with a boom crane out for delivery and will place them for you as well. They are about 3 times the size of a piece of plywood, and heavy. you would definately need a machine to move one, or about 6 groundies.