Overriding common/home in admin panel

Hello,
I am in need of building an extension that overrides the default dashboard (for additional authentication checks etc.)
The problem is ... there seems (unless I've missed something, in which case my bad) to be no way of doing it other than modifying the core which I would like to avoid. Any ideas on how to implement any of the following would be appreciated:

[*] Override common/home
[*] Change the landing page after admin login
[*] Point the landing page to a custom page (and possibly be able to attach permissions to common/home in the user groups page)

Thank you.

EDIT: I'm not trying to be too demanding but is there a way to hide all the inaccessible items rather than presenting the user with a "Permission Denied" message?

Anyone with a possible solution?

There are no extensions for the admin area. It is hardcode only at this time.

Ok. Thank you for the reply!

a110y did you have any luck there finding a way to hide the unauthorised menu links altogether?
I'm also interested in that. I don't want the e-commerce customer to feel 1. annoyed or 2. cheated (in a way).

In response to the first question best thing available currently is to use vqmod for your changes.

kyprios1 wrote:a110y did you have any luck there finding a way to hide the unauthorised menu links altogether?
I'm also interested in that. I don't want the e-commerce customer to feel 1. annoyed or 2. cheated (in a way).

Why would a customer have access to your admin panel?

I meant my customer of the e-commerce solution, not the final consumer.

Admin Dashboard and Menu Control has some of those features.