Muliple day "Rapid Fill" beverage mugs (that last for the length of your stay) are on their way to WDW hotels. They can be used at multiple Disney hotels, and even guests not staying at a disney hotel can buy into the program. Upcoming in the future will be an option to use the mugs at water parks.
The price breakdown is as follows:
1) Single day mug: $8.99
2) Two day mug: $11.99
3) Three day mug: $14.99
4) Four or more day mug: $17.99
Tracking of time of use is accomplished with specially designed radio frequency Identification (RFID) chips. Just name your drink(s) at the self-serve beverage station(s) of your choice.