3x5 trailer frame?

I'm having trouble finding a cheep trailer or someone to build me one up here in toront. All the trailers I've seen have got sides and tailgates which have to be ground off to build a teardrop. Also, prices seem to start around $700.00. I have a small utility trailer that is a 3x5 with 8" wheels that I enlarged the box to 4x5. It's not really a stretch to make this a 4x8 if I position the tear in the middle of the frame and lengthen the toungue, or even a 5x8. the wheels now are under the box, and by changing the shackles on the springs I could even put 12" tires on it. The trailer is rated for 1000 lb so If I'm carefull, I don't need to change the axle. Any thoughts????