Is it possible to do either a bulk delegation of assigned tasks or create a workflow that would reassign all the tasks that are assigned to a particular person, instead of opening each task and selecting the link to delegate?
there is DelegateAllTasks operation of Workflow.asmx web service.
so you will need to build a small workflow (or make the web service call by other ways) to get all users task delegated
note that this only works for new tasks, and task assigned to the user.
it doesn't delegate tasks that user already have assigned.
it doesn't work either for tasks delegated to the user.