Any suggestions?
My brother works at a cardboard box plant ane the cutting dies they use are mounted on birch plywood in roughly the same radius as what would work on your table. For blanks you might call: Plywood and Door Mfrs.( 708)-594-
5530. I used to get aircraft plywood scraps there and I think I saw some radius pieces laying around. (They had some gorgeous like 30-ply rock maple stuff laying around also.)