The heft of the trailers is the main reason I like them so much. When someone tells me my stuff is over built, or too heavy, I usually smile and nod, meaning that that is the comment I was hoping for. Like you, I prefer to build it once and forget about it.
I have a 30' macdon draper front. I use it on the swather and the combine. It came with an Unverferth trailer and it sucks. Tires are too small. Have to make all kinds of changes to use it without the combine adaptor etc.
Your trailers look very stable and the suspension should keep the fronts in fine tune when going down the road way. I really like the trussing you have done under the main frame. Looks like it supports those wide fronts you use very well. If your trailer was in the states for sale, I'd buy it and stop at the local paint shop on the way hope.
If you have any other projects you have done or are currently working on, please, please post them. Your skills and design are well refined and I want to see more. Home built and modified equipment is my main passion.