I don't have pics but in theory you should be able to use "interuptor" type levers on the drop bar tops with CP calipers. The "compression" of the housing that makes these work should not matter where the termination stop is: either on the (sidepull) caliper arm or on a (centerpull) hanger, AFAIK.
The limiting thing is that it might get awfully crowded in the cockpit: most of the time these are used on CX bikes with canti brakes and pretty wide bars, more room between levers and brakes than what you'd typically find on a mixte.