Actually that feature is already available in Windows Taskbar. I don't know about Windows 7's Superbar (I'll try it later, I'm using my Windows Vista workstation now), but in Windows XP/Vista (and maybe the older versions too), you can select multiple tasks in your Taskbar by holding Ctrl while clicking the taskbar buttons. So to achieve what you wanted, you just need to:
1. Press Win+D to minimize all tasks,
2. Click one task in the taskbar,
3. Hold Ctrl while clicking other tasks that you want to tile/cascade,
4. Right click on one of the selected tasks,
5. Choose one of the options (in Windows Vista: Cascade, Show Windows Stacked, Show Windows Side by Side).
As far as I'm concerned, unfortunately it doesn't work with Google Chrome.