Question regarding hanging shelves...

Hi all.. I'm a newbie here.. I'm actually not building a TTT per-se but would like to retrofit our 5-6 year old Wells Cargo 4x6 enclosed trailer to accommodate better storage for an upcoming trip up to the Pacific Northwest next month. Ultimately I'd like to pack some bikes and have a floor mount that can be used to hold down the front forks and was thinking that I could mount a set of shelves above the area over the front forks/handlebars for some small suitcases, boxes,etc.. Doing stuff like this ought to allow more stuff to be put in the trailer without wasting valuable space..
This particular trailer has square tubular steel (as far as I know -- still need to verify that its not aluminum) vertical pillars on 16" centers sandwiched between 1/4" plywood on the walls and the outer skin. I was thinking of attaching some 1x wood to the hidden metal studs to build out some shelves or possibly use something like some of the Elfa closet shelves cut to size (I've got some of this at home sitting around).
Anyway, what I'm curious about is whether any of you have any ideas on what my max-weight ought to be for the shelf & loading. Obviously I don't want the shelf to collapse or bend the steel tubing (not likely I'd guess). Also, if you've got suggestions to help tie things down on the shelf so they don't jump up-n-down (this trailer bounces a bit at freeway speeds unless its really loaded) that would be appreciated as well!
Below is what the trailer looks like (this is not my personally -- but mine looks just like it).
http://www.youngwellscargo.com/images/m ... online.jpg
This particular trailer has square tubular steel (as far as I know -- still need to verify that its not aluminum) vertical pillars on 16" centers sandwiched between 1/4" plywood on the walls and the outer skin. I was thinking of attaching some 1x wood to the hidden metal studs to build out some shelves or possibly use something like some of the Elfa closet shelves cut to size (I've got some of this at home sitting around).
Anyway, what I'm curious about is whether any of you have any ideas on what my max-weight ought to be for the shelf & loading. Obviously I don't want the shelf to collapse or bend the steel tubing (not likely I'd guess). Also, if you've got suggestions to help tie things down on the shelf so they don't jump up-n-down (this trailer bounces a bit at freeway speeds unless its really loaded) that would be appreciated as well!
Below is what the trailer looks like (this is not my personally -- but mine looks just like it).
http://www.youngwellscargo.com/images/m ... online.jpg