So, the biggest pickup i have ever owned was a toyota back in 1986 and a ford ranger some years later after i got out of the Marines, other than that i'm clueless about 1/4, 1/2, 1 ton, which is which...
As others have said, it isn't as much about length as pin weight. You will want a single rear wheel 1 ton (f350, silverado 3500, ram 3500) minimum for that size. You will still be limited by Wright with a SRW. A dually will buy you some more payload. There is some good info in the Tow guides here. Your best bet is to buy the trailer first and the truck to match the trailer.