Generally speaking, if a page's content isn't specific to one location, I'd advise against putting location information in the title of that page. You mentioned that you're aware of the option to make pages specifically for locations - that's really a much better solution than to stuff your title tags with city names. Rather than the title tags, however, maybe you could add content that specifically targets some or all of those locations (depending on quantity of course).
You could also add a footer section that links to each location page. The point is that there are many ways to up your rank in different cities. Using title tags on general pages may not be the best option, though. I realize this doesn't directly answer your question, but it's what I'd advise a client if they were to ask the same thing.
