Hi, it's still used today. It's called PSP or perforated steel planking. Today it's been replaced with nylon matting etc. The closest thing I can think of would be the AM PSP for the Tamiya SAS Landrover. You would need quite a lot of it. I would try making some myself I think, probably using plastic sheet and drilling or punching out holes into it and scoring in the lines along it. Hope this helps.
