Not sure what you are asking. If a single vehicle is over 26k you need a CDL(farm/Rv/military etc exemptions aside). If a combo is over 26k and the trailer is over 10k you need a CDL. You can drive a 25k truck with a 9k trailer with a ordinary license.
On the CDLs a class A means you can drive a single vehicle over 26k or a combo over 26k with a trailer over 10k. A class B allows you to drive a single vehicle over 26k like a dump truck but you can't pull a trailer over 10k unless the combo is under 26k.
As bdog said.
Why is this so hard to understand?
In my state (not sure of others) there is a farm exemption. You can easily get a 26k+ license by self certifying but it's for farm use only and within 150 miles and absolutely non commercial, no for hire. This is a class F. If you want to pull a trailer with a 26k+ truck (like a dump truck) you can with the F designation but if it's over 10k gvwr you need an E class license that you can also self certify to get.
I like self certification. We are adults. We can determine what we can and cannot do without govt permission. Self certification makes that possible with a simple form but they ask that you have 3 months or 3000 miles experience in the vehicle type. I'm supposing that you can get an F or E permit then drive with a higher certification driver for those 3 months. Or you can fib or you can use it farm only non road and do it that way.
TL: DR- If you wanna drive a vehicle over 26k you need something special. If you want to pull a trailer over 10k gvwr you need something special and your smile ain't gonna cut it.