If there is any way you can get her school to allow her to do self-paced online math instruction (we're working up to asking DS's school for that, but haven't done it yet), then I suppose she could compete with herself to see how fast she can progress through the material...
Have you considered trying to redirect her from math facts and standard elementary math curriculum topics to more beautiful and mysterious mathematical topics? I got a lot of mileage with DS by talking about the Fibonacci series, Pascal's triangle and prime numbers.
G is for Googol might get her started. This might rekindle an interest, and if it did, she wouldn't be competing with classmates on these topics.
I'm not sure that either of these ideas actually address your original question, though...
