Yep! I would start with local churches. If they have a commercial kitchen, odds are it's not very busy most days of the week and they are probably fairly affordable. Some churches have non-commercial kitchens--the key is to find one that has a health permit.
Next, local catering companies and restaurants. It's again, finding a business that is "closed" for certain times so working around that could be challenge, but it's possible to find a good fit. Catering companies often have "slow" days or time periods, and many restuarants don't serve breakfast or close from 2 to 5. Or, I worked at a restaurant that actually had a bakery & our baker started work at about 3 am, so being able to work that early might be a good fit for a place that doesn't use their ovens until close to lunch.
Also, cooking schools!
The local health department would be a great source as they have to inspect all these kitchens, so they might have a few ideas for a particular area.
And, if there is a local "restaurant association", they'd be a good source. In smaller communities, the Chamber of Commerce might help.
I'd post on Facebook and/or Twitter or even craiglist if I was looking for one, too.