How do you keep warm in your Truck bed?

if i ever live somewhere and it gets -60 im moving....nuff said

 

I currently use this for the air mattress:


Of course that's not insulation, that is just padding. My wife and I have an "Adam & Eve" sleeping bag that is rated to 0F. In between we put an egg crate style foam. This works great for the weather we camp in, but I know it won't work if it gets much colder.

I have grand plans to build a camping trailer using the bed of a Tacoma identical to my truck. Among other cool gadgets, I'm trying to figure out how to insulate the bed from underneath with a spray on insulation and add some type of 12V heating hooked to a deep cycle battery. I'm thinking like those heated mats you place underneath tile in the bathroom to have heated floors.

 

Maybe infrared heat.

 

I don't even know how to give a serious answer without saying a bunch of smartass comments first lol.