Shah, thanks for the Buddy Bike mention. CyciumX I see that you want a less expensive solution and at the moment there aren't any used Buddy Bikes that I know of for sale in your area. We sell fold-out foot pegs but NOTE: If you are ordering foot pegs for a bike other than a Buddy Bike, check your measurements prior to placing your order. These foot pegs fit a 31.8 mm (1.25") tube w/3.93" circumference. They can fit a smaller tube with a shim but not a larger one as the connection pieces are not flexible. I wonder why you don't want your stoker to pedal though? If she has physical limitations, cycling could be the best thing for her. Many riders take their kids on the Buddy Bike and use toe clips or cages to keep their feet on the pedals which even though they aren't contributing to moving the bike forward it is stimulating blood circulation and helping them get the feel of the coordination needed to ride a bike. If it's not physical but you are worried that she won't keep up with you, be careful. Riding any tandem without proper communication can lead to disaster. Another solution may be found at DaVinci Designs.
http://www.davincitandems.com/index.html It won't be cheap but I thought they developed a drive train that could allow the stoker to free wheel. Hope you find a good solution!