On the subjects of trucks: I think most companys that know there bottom line have most materials deliveryed, unless they are so big and have dedicated drivers.
So a hardscape truck is basically needed to bring the men, tools, and equipment to the job. Then pickup an extra yard or two or stone or sand and maybe some extra pavers. And to haul off the extra material/spoils at the end of the job.
I think a 550 size truck fits the bill perfect. The only think is they are 45k new and i can buy a sweet international for alittle more.
I think this post is just me thinking out loud. I proably made no sense.