Chris,

I just bought a kit that does what you are describing from Jameco Electronics
(part # 181833) for the not so steep price of $8.95.  You get all of the
components, including the 7 LEDs (2 red, 2 yellow, 3 green) and can set it up
for 1, 1/2 or 1/4 volt increments around  the 12 VDC center LED indicator.
It is mounted on a circuit board approx. 1 1/2 X 2 1/2".

www.Jameco.com

Hope this helps.

Roger