Smoker design question

[saltbranch]

I need some input on smoker designs. I want to build one that will be trailer mounted. Most of my experince is with side fire box. I have used one that had the fire box under the pit in the center that I really liked.
Here is what I have to work with. Its old heavy duty toolbox that's roughly 3'wx5'Lx3'deep made out of 1/4" plate. I am thinking of making it vertical with several shelves, not sure the best place for the firebox. I mainly use wood for smoking. Any ideas?
Thanks

 

[Dutch]

Can you post pics of the box so we know what you're working with? Sometimes having a visual aid will help get the creative ideas flowing. What are you going to fire that box up with? If'n you stand it on end you could put a propane burner in the bottom of it aka GOSM or Smoke Vault.

 

[saltbranch]

I should be able to get pics in a couple weeks. Next trip to the ranch I will be bringing it home. In its current form its a wing lid toolbox, built to fit a fullsize truck. Goes from the bed/floor of truck to about 8"s above the sides of the bed.
To fire it I was thinking more along the lines if wood. I have never used propane for bbq pit, myself. I have plenty of access to Mesquite for free. I am open for ideas like propane though. Just never have used it.
I'll get some pics.