Something similar is already available in IIQ using Forwarding User option available under preferences. Are you looking for anything specific in IIQ which is not possible using this feature currently?
Thanks for your reply but we are not looking for a forwarding feature but for a real delegation feature. This means that the feature:
should handle not only new workitems but also any past outstanding item
does not forward the items but allows another user to act on behalf of someone else (the orginal owner still sees the items and can perform actions on the items)
should work also with workgroups (if the original owner is in an approver workgroupand sees items in his approval queue, the delegated person should see these items in his approval queue as well); Notifications should be sent to the delegator and delegatee for the same items.