This bathroom is 5'-0" wide and 7'-8" deep. The knee wall ht is 5'-0" high. You can change the ht of the knee wall by a foot, and basically add 12" ht to the entire space. It would take us a couple of hours to revise the drawings to reflect this change. The roof is framed with trusses so it would just be a case of ordering the girder trusses deeper adding 12" depth to the heels of the mono trusses.
Let me know if you have other questions,