I Figured out that the best way to build a good cart, is to first, see what parts you can find either cheap, or through salvage, this includes the burner box, and the trailer, when you have that much, then you can go to say, Sams Club, buy your box to create the heatwell where your steel cambros will fit.
Once you have all the parts, get on your computer, and design the basic structure. You can use a variety of different programs to do this, I use MS Paint myself.
Now that you have all the basic parts, experiment, by making a basic box, fit all the pieces into the box, in the fasion that your cart will be, this way, you can make changes in the design if necessary. Once you have an idea what the cart will look like, begin building the cart frame onto the trailer. then, place the heatwell, burner box, and cooler into the framework to fit.
If everything looks good, remove the parts, and begin enclosing the frame with the skin, either metal sheeting, or plywood, if you use plywood, food safety requires that you paint the box both inside, and out. Cut the openings where the heatwell, cooler, and umbrella are to go, Access doors are beneficial to get to the Propane line, and to make certain that there are no leaks in either the heatwell, or the Gas line. If the cart is towable, some states require taillights.
If you like, I have some detailed images of different carts, as well as some of my own designs, if anyone is interested.
<message edited by Tinpan Chuck on Mon, 08/23/10 2:02 AM>