I built this on a harbor freight trailer I already had so that I could haul things back from my parents home. I would not have been able to build it so quickly without all of the reading I did on this forum.
My plan is that this will always be the utility trailer, but i want to put in side doors and a back door (the back door coming back from California was plywood screwed on) so that I can use it until I can build a regular teardrop. It has already been years, so who knows how long it will take.
On the return trip the dust cap came off one of the hubs and the wind sucked out the grease, so the axle and one hub are ruined. This happened two hours from home on a 1600 mile trip so I consider myself lucky.
Since I have to purchase a new axle anyway I am thinking of getting a 60" spring width axle and building a carriage like others have done so the wheels will be outside of the body.
Right now the body is off the trailer so I can repair the axle and repaint the frame as well as properly waterproof the bottom of the body.
The floor is 3/4' plywood, the sides are 1/2" plywood and the front and roof are 1/4" plywood with spars, the inside is bare with no ceiling yet. It is very solid.
Sorry to hear your axle bit the dust. I like fenders so I am going that way next. Now get you a mattress for that utility trailer and leave work behind. 
