I build tilt bed car haulers. What has been posted already is spot on.
Things to consider:
A steelie can be over loaded, You might break a spring but you can fix it pretty easy.
Do you want power tilt (electric/hydrailic or just the hand pump hydraulic.
Get one with stake pockets, you can use it as a large utility trailer as well as hauling cars, only need to add some boards to double its use.
I like to encourage the use of LT tires vs trailer tires. I have no trouble claiming that trailer tires are pretty crappy.
A roughsawn oak deck will outlast a treated lumber deck, plus the new treated lumber is corrosive to iron.
Make sure the trailer has a winch platform. I like to encourage the heavy duty hand crank boat winches, they may take longer, but you don't have to spend 5 bills for a winch that is getting the shit beat out of sitting behind the truck.
Opt for hand built fenders vs preformed. Mine you can actually drive a car over and not hurt them except for a bit of tire rub.
Here is a shortcut to my add. There is a pic of one of my car haulers.
Thanks
Kirk
Custom built Utility, Boat, & Snowmobile Trailers-Gift Cert. Available