Just finished striping a wrecked horsetrailer of all the walls, thinking I could do this and then use it as a nice flatbed bumper pull. It has nice 6000 lb torsion axles. HOWEVER, come to find out after alot of work I find that horsetrailer are unibodies and does not have a true frame.
so does anybody have any expierence with this or suggestions for how to add/finish a frame for it.

The one I cut apart years ago had a frame so thats no help. Put up some picts of what you've got to work with and we'll see what we can figure out. I don't see a frame being much of a problem if you build from scratch. I think the flat deck skidsteer trailer I looked at building last year was 5" chanel beams with 3" chanel cross members. The little trailer at work is all lite angle 7000 GVW. Not a true flat deck with the rail sides but useful. Northern tool sells a number of plan sets for trailer frames. I think the plan sets I looked at were less than $40. You've probably already got your axels / brakes/ lights/ coupler so most of your big ticket items are out of the way.

I'm gonna go with the obvious (as it's always the most overlooked) and ask if you've even bothered to have a look underneath the trailer's bed to see if it has a full frame to start with? I ask because everyone I've ever seen does.

OK I will get some photos of it tonight.
IBROKIT - Yeah that is what brought me to starting this thread, we looked underneath and sure enough their is no frame that goes from the front to the back. The frame rails that make the triabgle from the coupler stop when they should turn and run down to the back of the trailer.
thanks for the replies, like I said I will get some pics this evening.
DSW - thanks I will definitly check out northern tools website and look for those plans, that could be a big help to me.