I began my "portable neapolitan-style pizza oven" experiment over the weekend and glad to have come across this forum.
I bought one of these "cheap" infrared portable grills last year. I might be able to provide pics later, camera batteries weren't working. I can't post with hyperlinks so visit bbqgalore.com for the info on the "Turbo Sport Infrared Stainless Steel Portable Grill".
I put a single layer of unglazed quarry tile on the grill, but I might need another layer (still experimenting). The manufacturer says not to cook with the hood down and from some quick searching of this forum it seems this could eventually warp the hood.
The surface area of this grill isn't huge, but works fine for me. Another thing I'm considering, which I have come across before, is modifying this grill for two infrared burners and using it primarily for searing meat and cooking pizzas while using a separate large grill for normal grilling.
So right now I'm trying to determine a decent way to line a single layer of tiles inside the hood. Any ideas? I've thought about an extra grill rack, but lining the hood would be more attractive without crowding the oven. Hopefully this will prevent the hood from warping and increase the temperature above the bottom tiles.
I'll report my progress.