Thumbies give you 2 options. on the end. with the brake-lever, on the back.
Or right near the center , because of the figure 8 bend that is also in reach.
I've seen a Mustache bar like set-up, with road type brake levers
mounted on the front.
I suppose putting a reverse brake lever in the end, in back,
and an interrupter lever in the front
to have double brake locations, would work.
though the front one would need shimming to work on the 22.2 tube.