Truck box..need ideas

So I have this metal box. Its 30" long, 16" wide and about 12" deep.

I want it mounted flush against the back of bed (closest to the cab).

Problem is my bed cage. It fits right under it and that is awesome, except I wouldn't be able to open the lid.

My idea is to find some drawer sliders (or something similar) that I can potentially lock. So first, I unlock the sliders which will allow me to slide the box forward 8 inches or so and then I unlock the locks on the box itself.

Originally I was going to just put two bolts through the bottom of the box straight into the bed. Should I just mount the box 8 inches forward and say eff it to the gap I'll have between the box and back of the bed?

It fits right under and between this

 

Bolt a plate to the bed then bolt the sliders to that then weld a tab on the front of the box and attached one of these http://www.mcmaster.com/#90222a548/=fc46r7

Bam! Every time you need to get some thing outta the box just pull the handle up and the box forward

 

damn I didnt even think of putting a plate between the box and the bed. What kind of sliders should I go for? All I can think of are drawer sliders. I'm assuming ill need something thats maybe more weather proof?

 

Maybe?

http://www.mcmaster.com/#ball-bearing-carriages/=fc4lne

 

dang those are expensive..looking on ebay, I could probably find some cheap used ones..or something similar..thanks for the ideas

 

progress?