I was able to get this working:
https://github.com/jasonsperske/RetroPage/blob/master/RetroPage-init-script
I placed it in /etc/init.d and gave it 755 permissions. To make RetroPage compatible with this approach I had to update it to request port 1980 inside it’s source, though in the process I ended up figuring out how to combine start-stop-deamon with command line arguments, so if needed I can always pull the port 1980 code out. The service should run as the pi user and I’ve been testing it with my Raspberry Pi. I’ve plugged it into a 27′ CRT TV, it’s amazing, though now I’m working out the best video out settings, (I think I’m close) and I’m wondering if a restart device button and a config editor page wouldn’t’ be helpful.