Since you buy these vehicles as cab and chassis and you decide on the bed you can get what ever you want so get creative. You can go with a flatbed dump with optional sides both low and high. Bolt on Rack and or tool boxes if you need them, or took boxes under the bed so the boxes rise even in the dump position.
With ramps you can drive the tractor right on the truck and transport it that way depending on the weight bed length etc.
But certainly you can get one truck to handle all your needs. Find a great body builder and you will be in great shape.
And that's what I'm thinking Cat_Driver. I'd love to be able to put the tractor on the back and forgo the trailer all together. But what kind of bed length am I looking at? 14' - 18' starting to loose it's driveability then isn't it? Turning, Parking, Maneuvering on a service road for wood.