Engineer Trailer Plans and Blueprints

I build tiny home on wheels and are in need of an engineer who can design me a custom trailer made for my tiny houses. The task I want to accomplish is to have a trailer built just like the one in the images shown, but I want to engineer it to have 21" High tires on 5k axles supporting the trailer while having the deck go over the wheels without having to bother with wheel wells. So this is what I am hoping to make the sizes of the trailers with the following weight rating on each trailer: 100"x25-1/2' Trailer - 3 5k Axles With Brakes Rated at 15,000 LBS 100"x29-1/2' Trailer - 4 5k Axles With Brakes Rated at 20,000 LBS 100"x21-1/2' Trailer - 3 5k Axles With Brakes Rated at 15,000 LBS 100"x19-1/2' Trailer - 3 5k Axles With Brakes Rated at 15,000 LBS The Deck height of the trailer must be 24". I also like to have jacks on each corner of the trailer and 2 scissor jacks in front of the wheel wells. The last issue we wish to resolve on these trailers is we wish to create an opening in the middle of the trailer to allow drain pipes to move inside of the framing of the trailer. I know there is a lot to go over but I am willing to answer any questions needed. I need 4 plans made up for my trailers and may need to do more plans after this. Thanks Mike