Howdy Philip
When I built my cutting table, I went to the local glass / plexiglass dealer and bought a sheet of white poly board. The white poly board is the stuff that is used for cutting boards. I don't have a lot of room, I built my table 42inches x 6 foot. I talked with the sales person, and they are set up to cut what ever dimensions that I needed.
I don't know where you are, but you may check the phone book for exact location of the dealer.
Happy tooling
Tim