EDIT-2016-02-16:"Refreshing" this question because the method to shrink a VM discussed here is very efficient but has a major drawback: it deletes all VM snapshots. If someone knows how to shrink a VM while preserving snapshots, feel free to share!
EDIT-2016-02-16:"Refreshing" this question because the method to shrink a VM discussed here is very efficient but has a major drawback: it deletes all VM snapshots. If someone knows how to shrink a VM while preserving snapshots, feel free to share!