Wow. I finally get to contribute.
I replaced every bulb in the heater control and most of the lighted switches in our 99 OB with what are often called "grain of wheat" bulbs which I was able to get from my local Radio Shack.
Typical of Radio Shack, what they are called keeps changing, and sometimes they are sold as 14 V bulbs and sometimes as 12 V bulbs.
Radio Shack's current description is:
12 V Microlamps (2-Pack) Model 272-1092.
Current price is $1.99 for the pack of two.