dpkg --root functionality with apt-get?

[Bruce Edge <edgebruce@yahoo.com>]

Hi,
I need to make apt-get operate on a debootstrap built tree.
I don't want to chroot into it because I need to mount --bind my local 
debian mirror then.
Is there some -o option::whatever I can use to tell it to use this built 
tree as the root?

Lastly, is there a comprehensive list of all the supported -o options ?

Thanks, Bruce