To save you a little bit of time, this is the home page for Chicago Area Tandem Society:
http://chicagotandems.home.mchsi.com/ . I'm sure that somebody, maybe everybody, in that club will be able to help steer you in the right direction.
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Jeff
Learn from other people's mistakes. You won't live long enough to make them all yourself.
2004 Co-Motion Speedster
2010 (Specialized) Carmel comfort (my neighborhood bike)
2008 Raleigh comfort (wife's neighborhood bike)