Shouldn't be any guessing. It should be easy to figure out. If you buy a truck, whatever brand you chose, you can call a dealer and ask him to run the VIN. They should be able to tell you the GCWR for the truck. Subtract the weight of the truck from the GCWR and you get the maximum allowable trailer weight. My truck's GCWR is 55,000 lbs and I have a class A CDL. Empty it weighs 16,000lbs, so I can pull a 39,000lb trailer (but I wouldn't want to). Most I feel comfortable pulling is ~25,000lbs,. I have seen some single axle dumps rated up to 60,000 lbs, but most are in the 50-55 range. Simply & practically speaking, if you have a 50,000 GCWR and a dump truck that weighs 15,000 lbs, you can pull a 35,000lb trailer. First determine your weight of your machine, then find a truck & trailer that are rated to pull it.
I owned a 12 ton backhoe trailer to go behind my IH dumptruck. I still own a smaller equipment trailer. I sold the bigger backhoe trailer because it was simply too much of a hassle to store & maintain to use only 6-7 times a year. Most of the time it just sat there. Instead, I use a buddy of mine that owns a local rental agency. He moves my 18,000lb backhoe for about $100/hr. Most of the time it's under $200 to move my equipment since I work locally. I sold my trailer for $7,000. That pays for ~40 trips or 6-7 years of moving equipment. He moves HUGE stuff for people and it's all he does all day long. Trailers for big equipment are BIG 30+ feet long and a pain to store. They take up lots of space on my jobsites. If you have a big farm or lot, great, you have the problem solved.
I'm sure someone will be here shortly to refute everything I just said

, but I just make a living doing this stuff, so WTH do I know.
Anyway, hopefully it gives you some insight.