Having switched the R bars for the GT bars myself and examined both, I would say that this is not an option. Everything has it's place on the bars and the grip portion narrows to a standard very skinny diameter (7/8"?) from the 1 1/4" majority. The mechanisms for holding the switch gear on are propriatory, they are all but sealed units that do not split and require a special tool (luckily my dealer gave me one) to release them.
This is going to be one tough bike to customise the hell out of handle bar wise... what with CAN bus electrics and internally routed cables etc.!