Insert new values to a pick list based on the Account selected.

We have a requirement to have a look up icon for a custom picklist so that it displays only the values selected for a particular account, similiar to the system defined look up fields for accounts,contacts etc on the service request page.
Since custom look up fields cannot be created from field setup, I was thinking of using a selector report that will display the values from the custom picklist for the account selected in the service request object.

One of the requirements is to add new values if there is a limited set of values or no values returned for the particular account.