Not sure what you mean there. 2 ...2- 6 foot 4in end to end?
Two bunks, 6' 4" long, end to end? There's 166 inches between the rear of the seat and the inside of the rear door. Two bunks like that would fit, easily, as they'd be 152 inches.
One on each side at 6' 4" would certainly fit, too.
I'm not big on dropping down from the wall thing. I just had too many times in that old van where I had two skids on there and needed to sleep, but couldn't. Made Friday pickups for Monday delivery a nightmare (if I could have actually slept, that is). Even with just one skid I couldn't really get any sleep. Try to curl up on a skid and you'll see what I mean. hehe