I did a similar build, as you know (since you posted there a time or two
) not long ago-- here's the result:
http://www.finescale.com/fsm/community/forum/topic.asp?TOPIC_ID=6447
I never found any one piece set for the jerry cans...so I just took a piece of styrofoam and cut it to the size of the bed-- painted it black and glued it into the bed-- and put a layer of cans on top-- gave it a pretty good bit of depth. Make sure you are in no rush when assembling all those cans LOL