Would you be making sure these people were interested in a web presence before making the mock up. Are you assuming once presented with the mockup (that you invested hours) that it will make them want a web presence.
I have been working as a web design in my local market for years now and just cant see designing mockups without even knowing if they would be interested. If you are planning on having some templates and just swapping out logo and images it might pay off idk.