Base truck for stinger upfit?

Any chassis can be converted, just may have to stretch the frame or roll the axle a bit. The typical 9 car stinger is a 254" wheel base so they are not that difficult to find. You can rebuild any tractor to the exact wheel base you want, the hard part is finding the right BBC measurement. Bumper to back.of cab is critical if you are trying to maximize the load on the tractor head ramp.

The two trucks in your sample pics were both heavily modified to make into those units. @KANSAS TRANSIT is very familiar with the blue Freightliner as he was the one to have it built. I think Mike with the cabover is on here as well but I don't know his handle.

 

You are trying to reinvent the wheel, there are plenty of existing used equipment on the market for what you want to do.

 

Ask the place thats selling and installing the bed and stinger system for you how many feet are required from the back of the sleeper to the end of the frame. Then with that information in hand and a tape measure go find a truck that meets your needs with as close to that required length you need. Take it back to the stinger dealer and they can do the rest to make it work. The only difference between a tractor and a cab n chassis rig is the 5th wheel and that’s easily removed in an hour.