Collapse/Expand Pinned Icons

Similar to the notification area / system tray in XP, and requested for that in this topic, I'd like the same functionality for pinned items, with a little twist: when collapsed, it should show just the programs that are open/running. And ideally it would allow for pins to be set to always show, so I could have most hide when not in use but have some show regardless. Combined with making them smaller, as discussed in this topic, that would free up a lot of taskbar space.