You can rent a double stroller at Disney for $31 per day and a refundable deposit on a credit card.
"For Guests who require a stroller rental for multiple days, we offer a length of stay rental ticket where you make a one-time payment transaction for as many days of rental as you will need. Upon visiting a Disney Theme Park, show your receipt at the stroller rental location and you will be expedited through the queue with a reduced wait time."
The multiple day rental fee is:
$13.00 USD per day for a single-passenger stroller
$27.00 USD per day for a double-passenger stroller
http://disneyworld.disney.go.com/wdw...ailPage&bhcp=1