Just build a big carousel - cheaper, easier to maintain and mainland tourists will flock to it.
It could be populated not by horses and other animals, but giant-sized iPhones, Gucci bags, etc.
But on a more serious note, wouldn't the Kowloon Cultural District be a better location for this monster ferris wheel? For one thing it wouldn't be a strange blight on an iconic skyline, and passengers would have a better view of the actual Hong Kong skyline while in the ferris wheel...
Not sure what is this fad about biggest Ferris wheel. Just saw the one in Vegas (it has not yet started operations) but it did not look that impressive next to tall buildings and bright LCDs. I am not sure Hong Kong is an ideal location for such a thing.