I wanted the same thing and had a very bad experience as a result. I was planning a dinner for a group of roughly the same size; like you, I wanted to avoid the "typical" places you mention. I contracted for our group with an independent local restaurant (which I won't mention, it wasn't in Chicagoland anyway). What we found out the hard way was that, by choosing a restaurant with no experience serving groups of 100+ people, they weren't prepared to cook and serve that many people
at exactly the same time. Even though we had ordered all the food in advance, it took them well over an hour from the time they started serving the main course to the first table, until they had completely served everyone, and there were similar delays with the other courses. It was an absolute nightmare.
Since then - this is for a convention that meets annually - we have stuck with restaurants that already have a substantial ongoing business in private parties. We have achieved some of our best results at restaurants that have established a positive reputation among locals and have plenty of local clientele, but that also do a large business in private parties. That way, they are serving excellent, creative food and they have the experience to pull that off for a large group in the same flawless manner that they do for individual diners in their dining room. Places in the north or northwest suburbs that can accomplish this for you include:
Allgauer's (American, Northbrook) -
http://www.northbrookallgauers.comShaw's Crab House (seafood, Schaumburg) -
http://www.shawscrabhouse.comWildfire (steakhouse, Lincolnshire, Schaumburg, Glenview) -
http://www.wildfirerestaurant.comMaggiano's (Italian, Schaumburg, Skokie) -
http://www.maggianos.comAll of these have excellent food in a nice setting, but even more important, they all do quite a large business in private parties, so they have the facilities and experience to serve a private event smoothly and flawlessly.
The last three of these four are affiliated with Lettuce Entertain You, a Chicago-based group of restaurants with unique concepts, and they really have their act together when serving groups. Their event planners can help you not only plan your event, but also choose which of their restaurants best meets your needs. They have a website specifically for their private parties, with event ideas and other information to consider for planning a function. Check it out:
http://www.lettuceparties.comYou will need to talk with their banquet managers to see whether they can accommodate a group your size on the date you need (which is the very first question you should be asking them). I've been to big dinners at Allgauer's and I know they can handle a group your size (and they do it well). Based on their websites, it appears that Shaw's may be too small, and the only Wildfire location that might be adequate is Glenview. I'm not sure about Maggiano's.