I've been researching in advance of a 40th birthday extravaganza lin Chicago later this year and am looking for suggestions, resources or references to charter a small (15 pax) limo bus to hit up several breweries/pubs. To date, none of the tour operators I've noted online have overwhelmed me. - StanleysCup
Charter the Chicago Brew Bus and request Nik as a guide. It's his side gig, so I think he only does weekends. Goose Island Fulton's tasting room should be open by then, and they'll have a sour on tap every Saturday. I'd try to anchor a tour around there and/or Revolution's Kedzie taproom.
Another tour operator to check out is: http://brewscruisechicago.com You could also charter a Limo bus and just make your own brewery tour. Might be more expensive though. Windy City Limousine has Mini Bus options for 14 or 23 passengers.
If you hit up Revolution's Kedzie brewpub, you can book a private tour for your group. We did it last year for a friend's bachelor party and it was fantastic. I think it was $200 for the entire group, no matter the size, and we all got samples and our own behind the scenes look at their great facility. Highly recommended.