I have submitted with Sophie Demassey and Xavier Lorca a paper to the application track of CP'2011. We received the acceptance notification recently.
The paper is entitled "Bin Repacking Scheduling in Virtualized Datacenters". It tries to show the interest of Constraint Programing to provide a VM manager that can be specialized on demand to consider new placement constraints. We describe a model for the problem, some placement constraints, an implementation into Entropy and some evaluations from simulated workloads.
I saw by practice, that a rebuttal process may be useful. A reviewer was not really convinced about our stuff and change its mind from our rebuttal.
The preprint version is available here.