if you are still interested in such functionality, you may consider this extension: http://amasty.com/magento-advanced-permissions.html. It enables you to assign permissions to users for editing products and categories, Magento store-views and websites. No mess when having a lot of users in your store Ã¢â¬â vendors, category managers, etc Ã¢â¬â let them see and edit certain categories and products.
Please take a look at the screenshot below to get a proper idea of the extension’s options. Feel free to ask for any details!
Click thumbnail to see full-size image