my brother has a 94' s-10 reg cab pickup. He is 6 feet tall so drives with the seat all the way back. We've tried all kinds of truck boxes and none of them fit. I have a truck box right now that is for one 8. Bottom depth is only 7 1/2 in. and the top depth is 3 1/2 in. but yet it still doesn't fit. is there a store anywhere online that has thinner truck boxes? He'd also really rather have a 10 back there. The 10 were looking at has a top mount depth of 4 1/2 in. Can someone please HELP!! I'm desperate. Any info is appreciated.