Genuine Islamic Models for Takaful differ drastically from existing implementations. Kaiser Permanante and Health Clubs provide the right basis for Islamic models in this area. This needs to be researched further.
Moral Hazard, Incentive Problems et. arise from Western appraoches. Some of the issues are discussed in my encylopedia entry:Islamic Attitude towards Motives, Incentives of Economic Agents and the Role of Information
There are two versions of my Incentives/Motives article, short one for Encyclopedia entry, and long version to be published in JIEBAF. Both are available for download [here]