Probably a bit late now, since I presume these photos are behind the actual work beind done, but with the 6L90 being a GM transmission, did you consider pulling parts from a Silverado and making it column shift? Same goes for moving the parking brake to the floor. It would free up lots of space in the center console for a middle passenger, cooler, etc. Just a thought.
Some Fuso shifters are dash mounted, which could also be an option, though the parking brake is still next to the driver's right leg.