That's the basic idea.
douglasgoodwin wrote:it's an order of magnitude more complex than using a handful of components. It's not practical to build 50 of Arduino circuits
Actually the circuit would be simpler than using 555's, I can guarantee that. And simpler means easier to build. You don't need to duplicate the entire Arduino circuit. You just need a CPU.
Anyway, your original post was looking for a reasonably priced design service. I don't know any cheap ones but I am sure you can find someone. However, any experienced engineer will steer you away from using 555's for this, although for the record I don't really know what you are trying to do. Good Luck.