Here is what I threw together quickly after work:
holegenerator (v1.0.0).zip (3.4 KB)
I will try to get it hosted on GitHub like before.
I measured my own pegboard for default. It had quarter inch holes spaced one inch apart, so I made that the default.
Edit: It is now hosted here: Pegboard Hole Generator
Let me know if you run into any issues. I threw it together pretty quick.