And the bookmarks bar isn't a suitable replacement because?
Because you can open more bookmarks faster with one click.
let me if i understand: is it really possible to add an sidebar in chromium? if yes, the could to do like the bookmarks, as an "extension"
It is possible in the c code (e.g. like the developer tools window) but not as Extension you can download via the store. There are some extensions for Chrome, that add a "sidebar". The problem with these Extensions is: The "sidebar" is a new Window and not included in the Browser window. The usability of this just sucks, because of complicated resizing and because of overlapping of content.