Sleeping Platform Truck Bed Mattress - suggestions

First time poster but long time user of this blog - I have spent hours here doing research and customizing my truck to fit my lifestyle perfectly thanks to all of you.

I’m having issues finding a high quality sleeping pad/mattress for the platform I built in my long bed. I’m looking for something around 70-73 inches long X 54-57 inches wide. Being strange measurements it’s hard to find the perfect fit. The closest I have found is the Sea to Summit - Comfort Plus which is 72x50 but since I share that space back there often those extra 6-7 inches wide would really help.

I’m currently using a memory foam cut to the perfect dimensions that I roll up. It’s great as it was cheap, comfy, and customizable but it’s really clunky and takes away from the rear view when rolled up. I’m willing to pay for something thats just as comfortable but stores better.

Any advice would be appreciated! Thanks!