the bed is listed as 5 feet long, and the entire truck a bit under 6 feet wide. so I don't think you can get something thats 4x8 feet to lay flat.

Detailed dimension specs are.. right there.

Your other question is about.. bed vibes? That's not a real spec (for any truck builder). You can put a 100x4 sheet rock in any 4'+ wide bed.. best of luck to the person behind you. Don't forget the red flag (day) or light (at night).. in north america.