Fog computing has been proposed as one of the promising technologies for the construction of a scalable network infrastructure in the user’s vicinity, with the purpose of serving the tremendous amount of daily generated latency-sensitive Internet-of-Things (IoT) data. In provisioning the emerging IoT data in addition to the legacy Cloud services, the Cloud and Fog form a natural continuum of one another and the integration of these two key technologies would offer a promising infrastructure full with IoT resources for IoT data provisioning. In this article, we present iCloudFog, a reconfigurable architecture that enables an agile integration of Fog and Cloud networks. iCloudFog allows to construct different Fog types (i.e., wireless, wired, or hybrid) to fit the different characteristics of IoT devices and data, and Fog nodes. Due to its nature, iCloudFog presents several unique key research challenges that have not yet been addressed in existing literatures, such as network dimensioning and configuration, resource management/QoS, security/privacy, and positioning/localization. We discuss these challenges and suggest promising approaches to resolve them. Effective design and implementation of solutions based on the suggested approaches would allow iCloudFog to play a salient role towards the successful provisioning of future IoT applications and services.