Hotdog,
Send me a private message with your contact information, and I will send you a picture of how mine sits. Mine is a completely stock 1999 SR5 Extra-Cab four wheel drive with a 5-Speed. The only suspension modification I have made is I put Rancho RS 5000 shocks and struts when I first got it eleven years ago. Unfortunately, it is at my dad's house right now because my wife and I are doing some work in the backyard and garage and we don't have room for it at the time. It doesn't sit flat in the rear. It is strange if you are having trouble with your rear being flat because double cabs generally are not used for hauling because the bed is so tiny.
Take it easy,
Paul