use your amp/amps as your back seat rest.

 

That is actually an excellent use of wasted space. Looking under my seats (when I was running wire for my sub) I couldn't believe how much room is there, and how the metal brace is stationary - GREAT for bolting an amp to!

I wouldn't worry about temperature - yes, there is a vent under there, but if you bolt the amp to the brace, you're far enough away... and I don't know about y'all but the heat from my vents rarely goes above 80 degrees (MUCH safer than amps in the trunk on a hot summer day).