Access control for products

Idea
Have the ability to hide all or some products from guests.

Implementation A
Under Configuration > Customer Details: Add another option to Shop Status and Approval Status that says - 4. Must be logged in to view products.

Implementation B
Under Catalog > Categories/Products: Add another status option called "Hidden" (or similar), activating this causes the chosen category or product to be hidden to guests. Top level categories would still be visible in the catalog, but clicking the categories would take guests to the login/registration page.

A and B could be combined for overall or individual control.

Why?
This would allow shop owners to hide their products from guests, but still allow them to access the home page - where visitors are given a reason to sign up.

In the mean time, does anyone know how I can modify Zen Cart to do something like this now? All I want is to hide products from guests without blocking the homepage.