Modifying the Portal to include other objects

Hi,

Has anyone modified the FIM Portal to include other objects, for example: we would like to be able to create/edit/delete 'Positions' or 'Roles' in the FIM Portal.

Once a new 'Position' is created, then when you create or edit a User in the Portal, we would like the 'Position' attribute be a drop down box, with the ability to pick an existing 'Position'.

Is this possible?

Is this a lot of work?

Are there any samples online for something like this?

Thanks,

SK