A plugin for Grid 2 to display available raid CDs as an icon on the grid frames.
For instance, an icon of Spirit Link Totem is displayed on the Shaman as long as he has that cooldown available and ready.
Not sure how hard this would be to make, but I haven't found an addon out there that does this and shows raid CDs like this.
This gives a better overview of who can do what.
I don't know that presenting that info on grid itself would be particularly useful. The way I see it, the position of grid units wouldn't add any more information than you'd get from sequential list with names, and Hermes accomplishes that. It even does icon-only display if that's your goal.