You had better check local laws very carefully, you could be setting your self up for a large lawsuit if you get in an accident with LT tires on the trailer.
Also check with your insurance company if they will even cover a trailer with LT tires.
If you're traveling across state lines and a cop just happens to want to a do a check... well, then, if you're running tires that aren't DOT approved for the application you could be setting yourself up for a nice fat fine, too.
Considering the lawsuit aspect of it, too, I worked for a couple of tire shops that wouldn't mount anything on a trailer except for what the trailer called for. So there's that, too.
