We're thinking about getting a tandem. I'm a fairly serious roadie (about 3k/year) and my wife is not but she does like 30-40 mile rides from time to time. We'd use the bike for charity rides around the Chicago area, nothing too serious. The issue as we see it is the difference in our sizes. Can we find a decent tandem off the shelf without having to do something custom? Which companies should we be looking at and what price can we expect to pay?