I don't drive a tractor but here goes....we drive for Conway Now in a d unit. BUT...Conway pays tractors $1.05 all miles and they provide the trailers. Of all the Conway drivers we have spoke with most seem positive about how they are doing. Teams, like with most of the other companies, seem to do better.
I imagine, FedEx CC is the way to go if you want to make the big dollar per mile...if, and when, you get a load. I think they provide trailers as well however, they charge you for the use of them. I have no idea what they charge you. Hopefully someone who drives for them will see your post.