Hi Rog, Many of the LED bulbs will work on much lower than 12 volts like the little screw in bulbs that fit and work in a Jensen generator lamp post. At low speed they flicker with A/C current but in Jin's engine they should work fine. I would take a look on eBay or Amazon since Radio Shack is no more. A bulb a lot smaller than the flashlight bulb would be ideal for your power indicator lamp. At a dollar store you might find a string of left over battery powered Christmas lamps that are very small LED's that may be ideal for your purpose. If you don't have any luck, let me know and I'll chop up a little Christmas set.
Gil