It looks pretty simple. The whole axel units is just that a "UNIT". It appeares to be similar to a wheel axel unit on a RR train box car; in that it is a unit that the box (trailer frame) attaches to.
Adding a spacer (full channel) to the frame (welding it to the frame) would allow the axel unit to then be bolted to the full channel length spacer. The verticle plate that exists would be simply modified to accomodate the needed horizontal bolt.
I see where there would be no change in the camber. The tongue height...(hitch ball)... would be adjusted to accomodate the additional 4-6 inch elevation.
The corner stablilizing jacks on each corner of the trailer could be made to come on and off with a little modification.....as they really are a "HANG UP POINT" when going down a 3-4 inch step from pavement to gravel etc. The spare tire that is underneath the trailer could be placed on a verticle rear bumper pedistal....as the spare tire hangs down a lot as well.
The trailer was not designed for anything other than hwy pulls and RV Parks.....as it really sits low to the ground.
Thanks for all the input and I'll see what transpires. Tks again.
bejay