This was my quick and dirty Landspeeder X-34 for my sons 6th birthday party. I didn't plan on an instructable, so the photos are a mixture of construction and deconstruction. (it took up ALOT of room, I needed the garage back) It's also my first instructable, so excuse the rough edges.
Step 1: Chassis
The first step is to find a suitable chassis. I used an "Original KettCar" that we already had. I know that they have several models and sizes. It's pedal powered, although some of the younger kids needed to get a little boost to get all of the mass moving. Once you have your chassis, you need to identify your mounting points where you can build your sub structure. this method could be used for any sort of bodywork, although it could get quite heavy the more structure you have to build. I'm not sure how much more the drivetrain could handle.
Step 2: Sub frame
I Rested two 1"x10"x6' common pine boards on my mounting rails and measured between for my cross members. Once I had them tied together, they basically rested on the frame without any hard mounting points. I boxed in the steering wheel support at the front and the seat at the back to keep the sub structure from moving fore and aft. Once that is stable I added the 90 degree supports.
I attached "the shelfs", 1"x8"x6' common pine boards to create the horizontal surface or the "deck" structure. (no clear photo)