I actually suggested this a few years ago, and I still think it's a good idea.
Apple wouldn't need to buy Disney outright, all they need is controlling interest (50% + 1 share), so the cost is roughly half of what is being bantered here. I'm not sure how much of the Apple cash reserve is accessible, though -- Apple has tons of foreign profits that they can't bring back to the US without punitive taxes (which they are lobbying to change, of course).
And while, long-term, it would be a boon to the parks to replace the current Disney bean counters with Apple-inspired execs, the move for Apple would be primarily for the media side of operations -- a major broadcast network (ABC), the most-watched cable network (ESPN), a slew of other cable channels, a radio network, music labels, publishing labels, movie and television production.distribution companies, etc. Apple certainly seems to be looking hard at not just being the medium for consuming content, but influencing/controlling the mechanism for how the content is provided -- having major media players in its portfolio would help.
Getting back to the parks, I like the Apple synergy. The company vision of focus on the end-user experience is far closer to the original Disney philosophy than the "how can we nickle and dime our customers to death" attitude that seems to permeate the current organization.
All that said, I don't think it's going to happen, but I wish that it would.