Building TD on Top of Metal Sides of Utility Trailer

Hello all. I first posted this in the trailer section and got no responses. Maybe that was the wrong place, so I am posting it here.
I'm trying to plan my first TD. First is to find an appropriate trailer. The wife and I came across pictures on the web http://www.doityourselfrv.com/diy-teardrop-camper-made-recycled-materials/ where the TD floor was built on the railing around the trailer. This afforded a 6 to 8 inch space under the TD floor for what appears to be a lot of storage. Therefore, we have narrowed our search for a trailer down to a 5.5' or 6' by 10' utility trailer with flat (many have round pipes now) side rails.
I tried to do a few searches here to find other people who may have done this. I guess I'm not using the right search words, because I'm just not finding anything. If someone can point me in the right direction on this, I would appreciate the help.
Thanks,
Bubblehead (Greg)
I'm trying to plan my first TD. First is to find an appropriate trailer. The wife and I came across pictures on the web http://www.doityourselfrv.com/diy-teardrop-camper-made-recycled-materials/ where the TD floor was built on the railing around the trailer. This afforded a 6 to 8 inch space under the TD floor for what appears to be a lot of storage. Therefore, we have narrowed our search for a trailer down to a 5.5' or 6' by 10' utility trailer with flat (many have round pipes now) side rails.
I tried to do a few searches here to find other people who may have done this. I guess I'm not using the right search words, because I'm just not finding anything. If someone can point me in the right direction on this, I would appreciate the help.
Thanks,
Bubblehead (Greg)