Well, I can try to help from a Public Health regulatory perspective, but the alcohol laws are a different issue. Everything served in a restaurant needs to have been prepared at a licensed and regulated establishment, whether it be the restaurant itself (licensed by the local authority) or by a commercial establishment licensed by the USDA. Unless there is some exception for "non-potentially hazardous foods" in your local (or state) health code, which beer is because of it's low pH, you MIGHT get away with it strictly from a Health Dept. perspective. You could call up the local health department and ask them if you are allowed to bring in non-potentially hazardous foods to a restaurant for a one-off event (just tell them "cookies" or something because "homebrew" wouldn't sound good to them.)
Now, from a BATF perspective, serving homebrew in a licensed establishment... there's got to be something wrong with that from a regulatory perspective, but I don't know much about that.
Or you could just go and do it if the restaurateur will allow it. The restaurateur is more liable than you are since he is allowing it to be served in his establishment. Just as an example of people breaking public health regulations... I worked for a county that the head commissioner threw a "road-kill" banquet every year, serving game animals to the public for a fee. The county health regulations specifically stated that no wild game could be served to the public. I guess since he was head commissioner, he was above the law.