These probably weren't what you meant when you asked about shell dwelling cichlids but I recently got some shell dwelling Malawi cichlids. They're called Maylandia livingstonii 'Nakantenga Island' (possibly now called Metriaclima lanisticola).
They're a lovely fish that are powder blue with some yellow in the fins.
When they are young they use shells as cover but when they get larger they don't require the shells any more. A brooding female will spit her fry into a shell for cover.
Sam