second password layer for sudo

[R.L. Reingard]

hi all,
is it possible for us (in Ubuntu) to set a second password for a user in  
the sudoers-list?
somehow i start to dislike the fact that my user password is used for  
gaining sudo (root) privileges.
i would like to have sudo more protected. in 'man sudo' i have found the  
following:

The -a (authentication type) option causes sudo to use the specified  
authentication type when validating the user, as allowed by  
/etc/login.conf. The system administrator may specify a list of  
sudo-specific authentication methods by adding an "auth-sudo" entry in  
/etc/login.conf.  This option is only available on systems that support  
BSD authentication where sudo has been configured with the --with-bsdauth  
option.

who does know that 'auth-sudo'?
or does anyone have a better idea for a second password layer?

thats interesting stuff !
regards,
René