You can have multiple drawers containing mixes of any type of application, widget, or data, and all of this can be accessed while in other applications, although it will launch applications regularly, as opposed to doing some cool HALO windowed stuff.
While many ROMs include options for fast toggles or settings as a pull down, Sidebar Plus allows almost everything to be pulled out and displayed, executed, launched, toggled, or dialed. It comes default with three drawers set up, although you can set up more, and sub-drawers. I didn’t find much need to go past two personally (apps and contacts). The more drawers you add, the more precise your swiping will also need to be, but I think you could have five or so on a phone and not have any issues with it.
Download: Google Play