Dynamically changing the Roles and Menu options??

HI all,

I am working on a requirement where i need to change the roles and all the options dynamically(like the detailed navigation bar and dynamic navigation bar).

For example, User A logs in (who is an admin) and wants to see what user B is able to see when he logs in. So I will have a text box where user A(admin) gives the user id of the user B and then all the options (roles,the detailed level navigation bar options etc.) will be shown as it will appear for user B.

So for this, how will I dynamically ensure that the screen looks exactly simillar to what user B would see if he logs in ( i mean - roles, different options etc.)

If any one has any idea on this, please help me.

Regards,

Narahari