I often hear photographers say that they “can’t” shoot film anymore even if they wanted to. That is, well, horse-hockey (unless your film choice is not longer available, of course). You can and should make your work using the tools that work best for you. If a client comes to you for your style, they can’t demand it using their preferred tools. In a very crude analogy, that would be like hiring a plumber but telling him (her) that he could only use a hammer to fix your toilet.
You don’t have to be a jerk about it, but you do have to stand up for your process, whatever it is. As long as the client gets the final product in a form s/he can use, then how you get there really doesn’t matter. So shoot film, if that gives you the right control. You’ll just have to take care of the scans, etc., on your end (most likely) so that you can present your client with a digital file at the end of the process.
And in case you think that is unreasonable, take a look at this article about an illustrator and what tool he uses. 🙂