That's a good point Nancy makes - I hadn't thought of a defective comfort wheel! And she has had experience of the wheel causing this - so maybe the wheel is the way to go. Could you give the details of the wheel you want to order to someone and ask for it as a Christmas present. As Nancy says - it needs a good sized cage to fit a Syrian sized wheel in, but some Syrians are ok with an 8" wheel if they're not large Syrians, and that should fit.
That's probably the best you can do - if you can't go bigger on the cage. I know you got her current cage recently and it's a bit smaller than the 360 square inches. You could make a bin cage possibly if you parents would allow it.
You (or someone else) can order 8" wodent wheels here
Wodent Wheel 8 inch - Wodent Wheels