I installed a crysteel dump body with fold down sides, and I love it. If there is one feature to get, it is fold down sides. Its like having 2 bodies in one. Another option is the Stahl unit that has a utility body outside with a dump insert. It is a lot of money, but again one truck doing the work of two.
If I were to really dream big, a swap laoder system is tops. Any body you want on and off in less than 1 min.
Dino