I think a 10 segment LED bar graph with multi-colored LEDs (Imagine the first 5 LEDs are green, the next 3 are yellow and the last 2 are red) would be a great shield.
It would be a great output display for microphones, touch sensors, accelerometers, etc..

Can you draw a sketch of how you would want the LEDs laid out?

You could take a standard LED shield and replace the LEDs with the green yellow and red LEDs.

This is how I was thinking they would be...Just your standard 10 segment LED bar graph shrunk down to fit within the 20mm x 20mm Tinyduino profile.

(I know I could just swap different colored LEDs on the LED shield, but I have projects that would be a lot better with Liner LEDS instead of Rotary)

Here's a link to a sketch I drew, the file was to big to upload:/
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http://s1276.photobucket.com/user/Ben1342/media/10segmentledshield_zpsfcab9c83.jpg.html?filters[user]=137216718&filters[recent]=1&sort=1&o=0