Hybrid Distributed Computing Infrastructures (DCIs) allow users to combine Grids, Desktop Grids, Clouds, etc. to obtain for their users even larger computing capabilities. In this paper, we present an experimental study of the SpeQuloS framework which aims at providing QoS to Desktop Grid by provisioning on-demand Cloud resources. We describe the experimental platform which relies on Grid5000 to mimic both a Desktop Grid system and a Cloud system. Preliminary results are presented which shows the potential of the SpeQuloS approach.