A trailer with 7,000 lb axles with 95" hub face to hub face will give you about 93" between fenders. Most of the larger 50's trucks were about 89" from sidewall to side wall on the steering axle Using tires with weight capacity like aa ST235/85R16 Radial Trailer Tire, is 3,960 lbs. Here is a picture of a truck a guy hauled 1800 miles for me last week.

https://plus.google.com/photos/1081...05?authkey=CIva7Kzxwq68HA&banner=pwa

The steering axle will clear between the fenders, and you don't need the drive tires to clear between the fenders. He used a gooseneck, but I have a bumper pull tilt car hauler and a bumper pull utility trailer that I pull with a 2012 GMC 2500HD. I haul 10 to 11k loads with them, but I make sure my trailer brakes are adjusted up, I turn my gain up to 5 and make sure I have the tongue weight correct. I prefer to haul these kinds of loads with a semi, but there times when it is just too expensive to run a semi.

I use a trailer like this.
http://www.hhtrailer.com/Trailers/mxSpeed/index.html

It came with 3500lb axles. I put 7K axles under it and put a 15k Bulldog hitch on it. The rest of the trailer is built strong enough to handle 10 to 11k loads.