My mom is letting us sort it out for ourselves; it was my idea, my time/money, and its her rabbit. She just basically enforces what I say to my sister.
We never really got allowance, but phone time may work. (of course, I'd have to be the one monitoring her time, and I'd have to have my mom enforce it.)
As for cleaning and such, I already MAKE her do it if she hasn't, but very rarely does she follow through. Often I end up doing it for the rabbit's sake, or telling my mom (in which case, she's quick to start cleaning, but slow to finish the job.)
The phone thing might work, since that's all my sister does. But I'd have to watch her closely; she has a habit of getting old phones from friends every time we take her phone away. (She has 2 at the moment.)