Cloud Computing gets increasingly established in industrial practice as an option for modelling cost-efficient and demand-oriented information systems. Despite the increasing acceptance of cloud computing within the industry, many important questions remain unanswered. Issues related to the best software architectures decisions for cloud-based systems are faced with the question of appropriate techniques applying at early phase like requirements engineering. The goal of this paper defines a design of a mapping study to verify and identify the existence of relevant research gaps, which refers mainly to requirements models, tools or methods for cloud systems (SaaS). The conclusion of this mapping study design reinforces and actively encourages the necessity of the complete execution (and replication) of a systematic mapping study regarding the synergy of requirements engineering (e.g.: with model-driven issues) applied for a cloud computing.