In this paper we examine the feasibility of running message passing applications across clouds. Our on-going Unibus project aims to provide a flexible approach to provisioning and aggregation of multifaceted resources and facilitate resource usage for both resource providers and end-users. In order to achieve that the Unibus approach explores: (1) virtualization of access to diverse resources via proposing the Capability Model and developing specific resource drivers to concrete resources, and (2) soft and successive conditioning to enable automatic and transparent to the user's resource provisioning. Cloud computing opens exciting research opportunities for Unibus in terms of aggregation challenges. This particular work briefly describes main Unibus components and concepts. We also demonstrate how to employ Unibus to create an aggregated set of computing chunks provided by two commercial cloud providers and how Unibus virtualizes access to those resources. We also present how Uni...