Various plastic materials are generally available from commercial plastic distributors and occasionally from glass distributors. It is best to chat with the folks, as plastics vary widely in UV (sunlight) resistance and durability as well as surface hardness (important for scratch resistance. Also they are particular about which adhesives are used. Plastic such as plexiglass and lexan can be "worked" with regular tools such as table saws routers, etc. Also consider the opaque but durable polyethelene stuff, available at boat stores which resembles the white cutting boards of commercial kitchens. Good Luck!
