Here's another Schwinn Duo tandem at a bargain price:
Schwinn Duo Sport Tandem
Schwinn Duo Sport Tandem - $300
(Disputanta) 
condition:
good
make / manufacturer:
Schwinn
model name / number:
Duo Sport Tandem
1989-90 Schwinn Duo Sport Tandem. Paramount Design Chrome Moly frame, pearl white, 2 new seats, rear bag with rack, 18 speed Suntour XCD derailleur sets with bar end shifters, 48 spoke alloy wheels (27 x 1/4) with Continental Gatorskin tires (schrader valves), Dia-Compe AD-990 center pull brakes, 4 water bottle mounts (3 cages). An bike that is in really good condition considering it is 25+ years old. Not sure of the mileage since I am not the original owner. Paint is fair and it still has the original decals. Frame is large (I am 6'2" and my wife is 5'3") with the rear ideal for a smaller individual.