You will be approaching 1200 - 1400 pounds when complete.
A lot depends on your method of construction. You did not mention the tow vehicle. This will also be a factor into the equasion. Have you concidered a cargo conversion? Some turn out real sweet. My campin' buddy Jeff has a electric fireplace in his cargo conversion.
I would concider a heavier frame maybe an old popup
( these are generally real stout and 6x10)
or maybe 5x10 flatbed cargo trailer.
I have walked up to the door and knocked and been given 3 badly neglected trailer frames. I bought one recently for $60.00 and my 5x10 is built on pieces and parts from a 4x8 HF trailer I purchased on E bay for $75.00. One note on the HF and red trailers...Do yourself a big favor if you decide to build on one and reinforce the tongue with a stout center member. I stole the Idea from "nobody" (Thanks Harvey). There are pics in my album!
The barn build was built on a nice 5x8 cargo and I extended it forward for 2 extra feet. I had to replaced the badly bent tongue. It was $250.00 with nice tires and fancy wagon spoke rims and very well made.
http://www.tnttt.com/viewtopic.php?t=30307
There are unloved and unwanted small trailers setting in backyards and alleyways everywhere there is no need to cough up $400-$500 for a new unit. Just walk up to the door and ask the worst they can say is NO !
The frame kinda dictates the build unless you custom build the frame to match your plans.
I have found it more interesting to listen to the frame and build what it seems to want.
