Look on some of the Aussie sites for ideas if off roading is your goal.
They have some innovative suspensions.
You will probably have to design and build your own if you want something much different.
I went with a Flexiride that has adjustable swing arms and the ride height can be adjusted. I also changed the wheel wells for more clearance for 14"wheels and tires
. My goal is to get the ride height correct to match my VW Sportwagen with the bigger setup.
I had little problem aligning the Flexiride. I used steel wire to set the distance from witness points on the axle
to the hitch centerline. If the distances are the same then the axle has to be in the correct spot.
I would think it would be much more difficult to align two suspensions one on each side than one axle across the trailer. Probably the shell is not placed on the frame with any great precision either. What will count the the triangle formed by the wheel contact points and the hitch ball center. If you get this right then everything else should be good to go.
Some axles are adjusted for toe and camber by bending the cross tube, but I saw no evidence of this on my ALKO. Also the ALKO and it's "triangular" design would be difficult to modify by bending.
I think that Scamp lacks a little in the precision of assembly and you might be obsessing a little on this.
How much wear are you seeing now?
Perhaps one of the arms was bent by contact with a curb or something?