I had cage pans made for just a couple of dollars at a heating and air conditioning shop. I asked them to "hem" the edges so we wouldn't get any feet cut.
I also have some older cages in which the pans were looking really bad so I had new pans made for them, too.
Problem for you would be that if the cage is placed on end it would not have a slot to slide the tray in and out.
I saw Dude in his dog crate in your Garden album. His poor tail is hanging out. I see why you need a larger one.
Annie