Emerging IT service providers that aim at delivering supercomputing power available to the masses over the Internet rely on high-performance IT resources interconnected with ultra-high-performance optical networks. To adjust the provisioning of the resources to end-user demand variations, new infrastructure capabilities have to be supported. These capabilities have to take into account the business requirements of telecom networks. This paper proposes a service framework to offer Internet service providers dynamic access to extensible virtual private execution infrastructures, through on-demand and in-advance bandwidth and resource reservation services. This virtual infrastructure service concept is being studied in the CARRIOCAS project and implemented thanks to the scheduling, reconfiguration, and virtualization (SRV) component. This entity handles the service requests, aggregates them, and triggers the provisioning of different types of resources accordingly. We propose to adapt to envisioned heterogeneous needs by multiplexing rigid and flexible requests as well as coarse or fine demands. The goal is to optimize both resource provisioning and utility functions. Considering the options of advanced network bandwidth reservations and allocations, the optimization problem is formulated. The impacts of the malleability factor are studied by simulation to assess the gain.