To answer your question simply, yes it is 100% possible although not exactly how you described it. Check out the link below.
http://en.wikipedia.org/wiki/Artificial_island
However, is this likely to happen? Not in the slightest chance. I believe the palm islands in Dubai cost around $15 billion to create, and there is no way Cedar Fair could afford such a project. A boardwalk is much more affordable, and therefore far more plausible.