Seems like a silly thing to be in stealth mode about, plus it doesn't even sound like you have a product. (Not that a service business isn't a good thing)
Why are you even asking for help if there is no way to streamline it?
It's a service-business based off of customizing a product I have (think wordpress).
If the customization is purely the skin, then create a system for skinning, and get local designers to make skins. Then create a market place for them, and hire a bunch of people to make skins. (I assume it's skinning b/c your a graphic designer).
As an aside: I used to do custom wordpress themes but stopped because it was so much easier to have nice printed themes. Walk into the client with nice glosssy prints. I could buy the theme for $35 bux and resell for much more rather than deal with the nuances of the customer. Most customers just want it to look like some other guy's site anyway so why not provide that?
They actually would pay more for a standard theme because I could turn it around faster, and they were happier because it looked like everyone else's site. As a designer I never understood herd mentality, as a business man, I love it.
A template marketplace is coming, but it will take a little bit of time. Ideally I should be almost entirely removed from the equation once that happens.
As far as goes with the local designers, I've been going through an auditing process. The one problem is that since they'd need to deal with the clients directly, I need to be sure they are somewhat personable themselves.