Multi-cloud management enables to avoid vendor lock-in as well as improve the provisioning of cloud applications. However, the optimal deploy-ment of such applications is still impossible not only due to the dynamicity of the cloud and hybrid environments hosting these applications but also due to the use of potentially unsuitable forms or configurations of application components. As such, true optimality can only be achieved by accounting all possible com-ponent forms and selecting the best one based on both application requirements and current context. This gives rise to the era of polymorphic applications which can change form at runtime based on their context. A major pre-requisite for the management of such applications is their proper modelling. As such, this paper presents extensions on two well-integrated cloud modelling solutions in order to support the complete specification of polymorphic applications and presents an illustrative example of their use.