Where did you get this idea of making a menu board ?? I'm sure there can be many approaches to a menu board, but without getting too elaborate, it sounds like it would be very confining. Now, we have a 2' x 35' paper banner with a description of what we do and two or three samples of a like project running along the border of our ceiling along one side of the room. Then, they can play association or ask a questions.
Main problem with a menu board is..... what you call or refer to something is probably not what 90% of JOE PUBLIC is going to relate to.
You might call a site sign a job sign, while he might think of some flying advertisement on a website is a banner and not the 13oz kind you make. You'll end up explaining lotsa things that might not ever pertain to the sign the customer is looking to get.
At our shop, we have so many projects going on at any given time, if they need help, they can come look see, as long as they don't touch anything. When a customer can see first hand what you're talking about, it not only gives them confidence in your work and craftsmanship, but it also allows them to see a small cross-reference for who you do work. I've often heard people say, wow you do work for _____ and ______. Okay, let's get started on my job.
That's a great benefit to having a real shop. People will trust you with their money, because they know you're not a middleman just passing projects around boosting up the costs.