Here in Canada our voter ridings (precincts) do not have number ID's, only names.
It would be nice to be able to make custom fields as dropdown boxes for fields that need to contain a limited number of predefined options.
I've seen this implemented in some places where you can create a linebreak seperated list of the options. This works fine in some situations, however to make CiviCRM truly flexible there would need to be custom tables with autonumber IDs and a data field. The fieldtype of the data field should be user defined when the table is created.
I want to make a custom field that the user could select the voter riding for the contact. I would create a new field, choose dropdown box as the type. Then for the details of the dropdown box I would choose alphanumeric as the field type and then input (or import) all my riding data.