I talked to PBR products a few weeks back to see if they could make something for this they are currently making a diamond plate floor board but it does not cover the fire wall it just covers the bottom floor board hopefully I will hear back from them but the is a post on here where somebody uses the stuff the skid plates are made of to cover this area
I used some quarter-inch UHMW. I would recommend using 1/8 inch UHMW because the quarter was difficult to work with.
I basically broke it up into pieces that were easier to manage and make cardboard templates first. I used a halogen work light to soften the pieces so I could bend them into shape and then water to cool them off and set them. Here are some pictures for reference