Yes they recently introduced a medium duty, All you would need would be a sleeper and a box. I'd be all over a Volvo medium duty class 6 if it ever hits the market. The New Hino L series looks good as well. In the meantime I'm still waiting on the 2015 Sprinter to depreciate under $15k w/ 200k or under. We are getting close.
I had the first Western Star straight tuck, order the truck with length I wanted to fit the box. I had a class 8 with 16' box with 70" sleeper and Genset. If you plan on doing long haul I would go with a class 8 truck. stay away form business class truck as there mostly city trucks, they aren't really made for long haul and hard running. go to free want ad's on here. If your going to spend all day in truck make sure you have comfortable ride, air ride seats, air ride cab, air bags.. If you buy a used truck make sure you can look at maintenance reports , if you can't see them, don't buy that truck.
read all trucking papers you can get your hands on. read up on latest and greatest item's you want on your truck. plan it well and it will last a long time. if you are able go to truck shows and look at all toys , make a list of what you want, and cost to. then after you figure cost, what will make sense to put on truck. there are a lot of $1,500 to $3,000 options. when I got my Western Star , one of options I wanted was push button on dash to air tires up, after I found out that was $3,000 options at the time. I settled for cats eyes that was $75. options. you fill rear set of tires was air , eyes closed tires were at the right press. with live air from dash , required special rear and front axle .